Cat D Series Backhoe Loaders Service Training Manual – PDF DOWNLOAD

Service Training Meeting Guide 746

SERV1746-01 October 2002

TECHNICAL PRESENTATION

"D" SERIES BACKHOE LOADERS INTRODUCTION

"D" SERIES BACKHOE LOADERS INTRODUCTION MEETING GUIDE 746

SLIDES AND SCRIPT AUDIENCE

Level II - Service personnel who understand the principles of machine systems operation, diagnostic equipment, and procedures for testing and adjusting.

CONTENT This presentation discusses the design features, major components, and systems operation for the "D" Series Backhoe Loaders. Also included are descriptions of the operator's station and service points.

OBJECTIVES After learning the information in this presentation, the serviceman will be able to: 1. locate and identify the major components in the operator's station, power train, and machine hydraulic systems including the optional All Wheel Steer system; 2. explain the function of the major components in the power train, machine hydraulic systems and the optional All Wheel Steer system; 3. identify service points for the engine, power train, and machine hydraulic systems; 4. trace oil flow through the transmission and machine hydraulic systems; and 5. explain the operation of the starting and charging system.

PREREQUISITES Interactive Video Course "Fundamentals of Mobile Hydraulics" TEMV9001 STMG 546 "Graphic Fluid Power Symbols" SESV1546 STMG 595 "Introduction to Load Sensing Pressure Compensated Hydraulic Systems" SESV1595 STMG 630 "416B - 438B Backhoe Loaders - Steering and Implement Hydraulic Systems" SESV1677 STMG 677 "416C - 438C Backhoe Loaders" SESV1677 STMG 725 "416C - 438C Backhoe Loaders -Update" SESV1725 Technical Instruction Module "Autoshift Transmission for Backhoe Loaders" SEGV2678 Estimated Time: 8 Hours Visuals: 104 (2 X 2) Slides Serviceman Handouts: 18 Worksheets Form: SERV1746-01 Date: 10/02 © 2002 Caterpillar Inc.

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SUPPLEMENTARY TRAINING MATERIAL STMG 629 "416B - 438B Backhoe Loaders–Introduction" STMG 630 "416B - 438B Backhoe Loaders–Steering and Implement Hydraulic System" STMG 604 "416 - 438 Series II Backhoe Loaders–Engine, Power Train and Electrical Systems" STMG 605 "416 - 438 Series II Backhoe Loaders–Steering and Implement Hydraulic System"

SESV1629 SESV1630 SESV1604 SESV1605

REFERENCES Service Manual 416D Backhoe Loaders Service Manual

RENR3570

Parts Manuals 416D Backhoe Loader BFP1-Up 416D Backhoe Loader BGJ1-Up 416D Backhoe Loader (G Version) BKG1-Up 420D Backhoe Loader FDP1-Up 420D Backhoe Loader BLN1-Up 420D Backhoe Loader BKC1-Up 420D Backhoe Loader BMC1-Up 430D Backhoe Loader BNK1-Up 430D Backhoe Loader BMC1-Up 424D Backhoe Loader BGP1-Up, BKR1-Up 428D Backhoe Loader BLL1-Up, BNB1-Up 428D Backhoe Loader BMT1-Up, BNS1-Up 438D Backhoe Loader BPE1-Up, BPN1-Up 432D Backhoe Loader BLD1-Up 442D Backhoe Loader BRG1-Up, BRY1-Up

SEBP3202 SEBP3236 SEBP3241 SEBP3203 SEBP3204 SEBP3237 SEBP3238 SEBP3205 SEBP3206 SEBP3207 SEBP3208 SEBP3209 SEBP3211 SEBP3210 SEBP3212

Operation and Maintenance Manuals 416D Operation and Maintenance Guide 420D/430D Operation and Maintenance Guide 424D/428D/438D Operation and Maintenance Guide 432D/442D Operation and Maintenance Guide

SEBU7398 SEBU7399 SEBU7400 SEBU7401

Specalogs 416D Specification Sheet 420D Specification Sheet 430D Specification Sheet

AEHQ5419 AEHQ5420 AEHQ5421

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TABLE OF CONTENTS INTRODUCTION .................................................................................................................5 ENGINE................................................................................................................................25 Fuel System.....................................................................................................................27 ELECTRICAL SYSTEM .....................................................................................................34 POWER TRAIN ...................................................................................................................39 Standard Transmission....................................................................................................39 Autoshift Transmission ...................................................................................................44 Axles and Brakes ............................................................................................................55 STEERING AND IMPLEMENT HYDRAULIC SYSTEMS..............................................62 Steering and Implement Pump Operation.......................................................................74 Loader Valve Groups and Steering System ....................................................................80 Backhoe Valve Groups..................................................................................................110 All Wheel Steer System (AWS)....................................................................................133 OPTIONAL MACHINE SECURITY SYSTEM (MMS) ..................................................134 CONCLUSION...................................................................................................................136 SLIDE LIST........................................................................................................................137 SERVICEMAN'S HANDOUTS.........................................................................................139

"D" SERIES BACKHOE LOADERS INTRODUCTION

© 2002 Caterpillar Inc.

1

INTRODUCTION • Center pivot models: - Standard controls - 416D - Pilot controls - 420D and 430D • Sideshift models: - Standard controls - 424D - 428D - 438D - Pilot controls - 432D - 442D

The "D" Series Backhoe Loader Family is the latest generation of Caterpillar Backhoe Loaders retaining many of the features proven on the "B and C" Series machines along with additional performance and design improvements.

This presentation discusses the systems, major components, and features of the "D" Series Backhoe Loaders.

The "D" Series machines include the 416D, 420D and 430D which are equipped with the center pivot backhoe. The 420D and 430D feature pilot controlled implement hydraulics.

The "D" Series also includes the 424D, 428D and 438D sideshift models which are popular in Europe. Additional sideshift models include the 432D and 442D with pilot controlled implement hydraulics.

The new machine series features new paint themes to provide a bolder image.

SIMILARITIES WITH FORMER MACHINES

• Engine • Thermal Starting Aid • Radial Seal Air Filters • Standard Transmission • Steering • Brake System • Hydraulic Pump • Mechanical Implement Controls • IT Linkage • All Wheel Drive

2

• Similarities

The "D" Series machines have many similarities to the machines they are replacing.

The basic engine, standard transmission and steering systems are the same as before.

The hydraulic brake system has multiple disc brakes and inboard planetaries in the rear axle. The brake system is the same except for the master cylinders being mounted differently than in the "C" Series machines.

The hydraulic pump and controls are virtually the same as the "B" and late production "C" Series, except for changes in operating pressures and flow rates.

Most of the daily service fill and check points can be accessed through the hinged engine hood.

DIFFERENCES FROM FORMER MACHINES

• Operator's Compartment • HVAC • Fuel Pump • Starting and Charging System • Autoshift Transmission • Hydraulic Tank • Reverse Signal System • Stabilizer Valves • Ride Control System • High Rotation Buckets • Pilot Controlled Hydraulics

3

• Differences

The "D" Series machines feature several changes over the previous models to improve operator comfort and machine performance.

The operator compartment features new console layouts. The heating, ventilation and air conditioning components are located near the floor and provide significant improvements to air circulation.

The fuel pump has been changed to the type also used on the 914G Wheel Loader.

The electrical system has changed significantly from the previous models.

Two fuse and relay blocks are located below a cover on the right side console.

The autoshift transmission is the same as the power shift transmission on the "C" Series except for the change in the software to convert to autoshift.

The hydraulic tank has been redesigned. A expansion tank is no longer required. A tube has also been added to make draining the tank much easier.

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The signal line routing has changed. With the reverse signal system, the last resolver in the signal network is in the loader valve group instead of the backhoe valve group as per previous backhoe models.

Some machines are available with pilot operated controls for the backhoe valve group or for both the backhoe and the loader valve groups. The pilot controls provide reduced lever efforts.

The stabilizer valves on all machines are pilot controlled and are different in design from the previous versions.

Ride Control is similar in operation as before, however, the system design has been modified.

Due to changes in the backhoe linkage, a single pin location is able to provide improved performance for all backhoe operations. Previously, two pin positions were used.

"D" SERIES BACKHOE LOADERS CENTER PIVOT FEATURE DESCRIPTION

416D

3054 Naturally Aspirated Engine 3054 Turbocharged Engine 12-V Electrical System Standard Transmission Autoshift Transmission (option) Single Tilt IT Linkage Ride Control Pump Flow 139 L/min (37 gal/min) Pump Flow 163 L/min (43 gal/min) Dynamic Bleed Steering Maximum Pressure 20 685 kPa (3000 PSI) Maximum Pressure 22 754 kPa (3300 PSI) Mechanical Hydraulic Controls - Loader Mechanical Hydraulic Controls - Backhoe Pilot Hydraulic Controls - Loader (IT only) Pilot Hydraulic Controls - Backhoe Auto Up Stabilizers All Wheel Drive (AWD) All Wheel Steer (option) Machine Security System (option)

S O S S S O S S S S S

O

420D

SIDE SHIFT

430D

424D

428D

438D

432D

442D

S S S S O S O O

S S S O S O O

S S

S S

S S

S S

O S O O

O S O O

S = Standard

S S S O O S O

S S S O

S S S O

S S S O

S O

S O

S O

S S

S S

S S

S S

S S S O

S S S O

S

S

O

O S

O

O

O S O O

S S O S

S S O S O O

S S S O S S S S S

O

O = Option

4 • "D" Series comparison chart

This chart compares each "D" Series model to each other and reflects some of the various options and features of each machine.

The 416D and 420D compete in the same size class and are replacements for the former 416C. The 416D is a lower cost version of the 420D and has fewer available options. The 416D also has slightly lower performance ratings than the 416C, while the 420D has higher performance ratings.

The 430D replaces the both the 426C and 436C in the marketplace.

The 420D and 430D feature pilot controls for the backhoe, while either mechanical or pilot controls are used for the loader. Loader pilot controls are only for machines with IT linkage.

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Additional comparisons can be made to the sideshift machines. The 424D is the sideshift version of the 416D. The 424D, 428D and 432D compete in the same size class. The 432D is equipped with pilot controls for both the loader and the backhoe. The other two machines feature only mechanical controls.

The 438D and 442D compete in the next higher machine class. The 442D is equipped with pilot controls.

The machine security system will only be available on the sideshift machines during the initial machine introduction. The center pivot machines may have this as an option in the future.

All Wheel Steer (AWS) will not be made available on center pivot machines until further notice.

5

• Cab features

Several cab choices are available including an enclosed Roll Over Protection System (ROPS) cab as shown and and open ROPS. The open canopy machines can be equipped with a air suspension vinyl seat, tilt steering wheel, 12 Volt power supply, phone clip, a lockable left side storage space, drink holders and floor mats.

On the 420D and 430D, the standard cab features an air suspension fabric seat, tilt steering wheel, 12 Volt power adapter, phone clip, a lockable left side storage space, drink holders, floor mats, two doors, eight working lights and opening rear windows. The machines are radio ready.

The deluxe cab has in addition to above, a nine-way adjustable air suspension seat, auto-up stabilizer controls and additional system monitors. These monitors are for the voltmeter, fuel water separator, engine air cleaner and hydraulic filters.

The 416D is not available with the deluxe cab. The standard cab also features a single door which is on the left side of the machine. A cab upgrade is available with two doors and air conditioning.

NOTE: Sideshift machines have similar cab features as the center pivot machines. Refer to the appropriate operation and maintenance manual and specalogs for more information on all models.

1 3 2

5 6

8

9

4

7 10

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• Machine controls: 1. Steering wheel 2. Transmission directional selector lever 3. Turn signal/wiper control lever 4. Four speed transmission shift lever 5. Loader control lever 6. Auxiliary control lever 7. Differential lock 8. Service brake pedals 9. Governor pedal 10. Parking brake lever

When sitting in the operator's seat and facing the front, various machine controls and features can be identified.

The cab shown is a machine equipped with mechanical loader controls levers (5 and 6) to operate the front loader bucket with a single tilt cylinder.

The four speed transmission shifter (4) and directional selector (2) are for machines equipped with the standard transmission.

If the parking brake (10) is engaged when the operator selects FORWARD or REVERSE, the fault alarm sounds.

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5

3 1

4 2

7

• Machine controls: 1. Autoshift speed and direction shuttle control 2. Loader joystick 3. Auxiliary buttons 4. Thumb switch 5. AWS position indicator gauge

On machines equipped with a autoshift transmission, the speed range selector is part of the directional shuttle control (1).

Shown is the loader pilot joystick (2). The two yellow buttons (3) on the joystick can be used to control an auxiliary function or for All Wheel Steer (AWS). AWS will only be available on sideshift machines initially.

The thumb switch (4) provides input to the Auxiliary Control Module (ACM). The ACM directs a variable current to two proportional solenoids mounted on the loader auxiliary valve.

A switch (not shown) on the front of the joystick is used to downshift the transmission or neutralize it depending on how long the switch is held.

In Autoshift Mode, if the switch is depressed for less than one second the transmission downshifts. If the switch is held longer, the transmission is neutralized. In Manual Mode, the switch will not downshift the transmission.

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6 1

2 3 5 4

8

• Left front console: 1. Alert indicator panel 2. AWD switch 3. Quick coupler pin switch 4. Continuous flow switch 5. Optional washer/sprayer switch 6. Transmission NEUTRAL lock switch

The switches on the consoles will vary depending on how the machine is configured.

The alert indicator panel (1) includes: left and right turn signals, high beams, parking brake and ride control.

The All Wheel Drive (AWD) switch (2) has three positions. One position is for AWD OFF, another for AWD ON, and the other position for AWD ON only when the brakes are applied. This last position allows for better machine braking by locking up the entire driveline. In affect, all four wheels are used to brake the machine even though the front wheels are not equipped with brakes.

A quick coupler pin switch (3) is used on machines equipped with the Integrated Toolcarrier (IT) style dual tilt cylinder bucket and parallel lift arms. The switch is used to release or lock the coupler pins from an attachment.

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The continuous flow switch (4), is an option that works with the proportional solenoid controlled loader auxiliary circuit. The switch is momentary. After the desired flow rate is selected with the loader joystick thumb switch. Press and release the continuous flow switch.

Then release the thumb switch. The feature is used with brooms or other attachments where continuous flow is required.

The optional washer/sprayer switch (5) is used to control a separate function such as a washer for a broom.

The transmission NEUTRAL lock switch (6) prevents the transmission from being shifted into a direction. The directional selector lever can be moved, but the transmission will not shift until the lock switch is turned off.

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1

2

5 3

4

9

• Right front console: 1. Flasher 2. Autoshift switch 3. Ride Control switch 4. COSA roading light switch location 5. Horn

The autoshift switch (2) allows the operator to switch between Manual or Autoshift Modes. In autoshift, after the operator selects the maximum speed range on the shift selector lever, the machine automatically shifts the machine based on ground speed. Maxium speed gear in autoshift is fifth, while manual is limited to fourth. The shift lever only shows up to fourth gear; however, in autoshift the transmission will shift into fifth gear based on ground speed.

The Ride Control switch (3) is used to select the different modes of operation. The optional Ride Control system provides a smoother ride when the machine is driven over rough terrain. On machines equipped with autoshift, the transmission ECM monitors the position of the Ride Control switch and determines when to operate the Ride Control system.

If the machine is equipped with AWS, a gauge and switches to select the AWS mode are also mounted on the right front console (not shown).

(AWS will discussed later in this presentation.)

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3

7

2

4

5

6

1

10

• Loader controls: 1. Pilot joystick

The loader controls are located in the side console.

The side console is equipped with additional gauges, switches and controls.

2. Alert indicators 3. Key start switch 4. Hydraulic lock switch 5. Governor lever 6. Boom lock lever 7. Stabilizer pilot control levers

The alert indicators (2) include: engine oil pressure, coolant level, charging and brake level.

The additional switches and controls on the side of the console vary with machine configuration. Gauges include: tachometer, fuel level, coolant temperature and power train temperature.

The key start switch (3) no longer has an accessory position as did the "C" Series machines.

The hydraulic lock switch (4) controls a pilot shutoff solenoid valve on machines with pilot controls. The switch energizes the pilot shutoff solenoid when the key start switch is turned ON to allow pilot oil to the joysticks to operate the implements.

When the key start switch is turned OFF or the switch is moved to the LOCK position, the joysticks are disabled.

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With mechanical controls, the hydraulic lock switch controls an optional hydraulic shutoff solenoid valve instead. When the hydraulic lock switch is moved to the LOCK position, the valve is energized and blocks supply oil to the backhoe valve group when roading the machine.

The rear governor lever (5), boom lock lever (6), and stabilizer pilot control levers (7) are also located in the side console.

The action alarm (if equipped) will sound when one or both stabilizers are raised if the transmission direction control lever is shifted from NEUTRAL. The stabilizer control system may feature auto-up, which holds the levers in detent for a set time to automatically raise the cylinders. The timer can not be adjusted.

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2

1

3

11

• Mechanical backhoe controls: 1. Swing and boom 2. Stick and bucket 3. Boom lock lever

When the operator is facing the rear of a machine on, the standard backhoe controls can be identified.

The standard control pattern for the "D" Series is the same as on all previous backhoe models. The long lever on the right (2) is used to control bucket and stick. The long lever on the left (1) is used to control the boom and swing.

The boom lock lever (3) has been moved to the side console.

A pedal or pedals (not shown) on the floor are used to control the auxiliary functions like the E-stick or a hammer.

To satisfy the needs of the customer, optional control configurations are available.

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1

2

3

4

5

6

3

12

• Pilot operated backhoe: 1. Stick and swing 2. Bucket and boom 3. Pods 4. Pilot control pod lever 5. Swing lock pin 6. E-stick pedal

The backhoe controls for machines equipped with pilot controls are shown.

The pilot control pattern for the "D" Series is the same as the Cat excavator pattern. The joystick on the right (2) is used to control bucket and boom. The joystick on the left (1) is used to control the stick and swing. A switch to activate the horn is part of the left joystick.

The joysticks are mounted to pods (3).

The pilot control pod lever (4), locks the joystick pods until the operator releases the pods in order to move the joysticks for and aft to an ergonomically correct position.

E-stick pedal (6) is used to control an auxiliary valve through mechanical linkage. On some machines an additional pedal (not shown) can be used for an additional auxiliary function.

To satisfy the needs of the customer, optional control configurations are available including the Cat backhoe pattern.

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1

2

13

• Pattern changer valve lever:

An optional feature on machines with joystick controls is a pattern changer valve (not shown) mounted to the inside of the frame on the left side of the machine.

1. Lever 2. Hole

The lever (1) is in position #1 for the excavator control pattern.

The lever can be moved to a different position to change from excavator to a backhoe control pattern.

To select the backhoe control pattern the bolt must be removed from the end of lever. The lever can then be rotated to the lower hole (2) for position #2.

The bolt is then reinstalled in the hole to hold the lever.

The #1 and #2 are stamped into the frame.

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14

• "D" Series buckets: - Bucket stop plates

The "D" Series backhoes feature "high rotation" backhoe linkage. A single pin bucket position contributes to 205 degrees of rotation. This is suitable for all applications eliminating the need to change pin positions as was done on all previous backhoes.

An integral lifting eye (not shown) is a standard feature of the bucket linkage.

Bucket stop plates (arrows) allow "C" Series buckets to be used on "D" Series machines. When a "C" Series bucket is attached, the plates must be moved to the other side of the linkage to limit "C" Series bucket travel.

Without the stops, the "C" Series buckets will contact the stick.

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1

2

8

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4

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15

• Service points:

Most daily service fill and check points are located below the hinged hood.

1. Air filter housing 2. Engine oil fill tube 3. Engine dipstick 4. Hydraulic tank fill tube 5. Transmission fill tube 6. Air filter indicator 7. Washer fill bottle 8. Brake reservoir

Radial seal air filters are used on these machines.

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16

• Hydraulic sight gauge (arrow)

The hydraulic sight gauge (arrow) is located on the left side of the machine in front of the cab on the loader tower.

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4 1

5 6

2 7

9 3 8

17

ENGINE • Service points and components: 1. Radiator fill cap 2. Power train and implement hydraulic system oil cooler 3. Condenser 4. Compressor 5. Fuel filter 6. Fuel pump 7. Fuel fill tube 8. Fuel tank drain plug 9. Decal

The "D" Series backhoe loaders are powered by direct injection, four cylinder, Caterpillar 3054T diesel engines. Most of the models are turbocharged. The 3054B naturally aspirated engines for the 416D and 424D use similar components, but are not equipped with an engine oil cooler.

The 3054B is the specific model designation for the 103 mm bore engine. to meets EPA Tier 1 emissions. The increased bore size gives it a total displacement of 4.43 liters. All other 3054 engines have 4.0 liter displacement. One other significant difference is that the 3054B is linerless. All other 3054's are built with dry, replaceable liners.

In front of the radiator is a combination power train and implement hydraulic system oil cooler (2). The two systems are separate, but use a common cooler assembly.

If the machine is equipped with air conditioning, the condenser (3) is mounted at the front of the engine compartment. The air dryer (not shown) is located behind the rear axle.

The decal (9), identifies the access point behind the frame to drain the fuel/water separator.

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1 4

2

5

3

18

• Engine compartment components: 1. Thermal starting aid 2. Fuel lift (priming) pump 3. Starter 4. Alternator 5. Radiator

Shown here are the components on the right side of the engine compartment.

The standard alternator (4) is rated for 55 amps. An optional 90 amp alternator is also available.

The cooling system features an automotive-type radiator (5).

NOTE: The thermal starting aid was called the start aid coil on "C" Series machines.

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FUEL HYDRAULIC SYSTEM ENGINE RUNNING BOOST PRESSURE

BOOST CONTROLLER

TRANSFER PRESSURE REGULATOR

MAIN FILTER

WATER SEPARATOR

FUEL TANK

FEED PUMP SHUTOFF SOLENOID

FUEL RETURN CHECK VALVE

INJECTOR TORQUE TRIMMER

VENT ORIFICE DELIVERY VALVE ROTOR

CAM RING

TRANSFER PUMP

ROLLERS METERING VALVE

PLUNGERS

SHOES SCROLL PLATES

AUTOMATIC ADVANCE MECHANISM

FLAT HYDRAULIC HEAD COLD ADVANCE DEVICE

ORIFICE CHECK VALVE LIGHT LOAD ADVANCE VALVE

LATCH VALVE

19 Fuel System • Fuel flow through fuel system: - Water separator/fuel filter - Lift pump - Fuel filter - Distributor-type fuel injection pump - Injectors - Return to tank

All components shown in the schematic except for the fuel tank, water separator/fuel filter, lift pump, fuel filter and injector are part of the fuel injection pump.

The feed or lift pump is used to move fuel from the fuel tank to a higher level on the machine. The pump is also used to prime the system.

The water separator removes water from the fuel. Since the fuel injection pump is lubricated by fuel, it is extremely important that water does not enter the pump. Water will cause the pump to malfunction and will lead to the rotor and plungers locking up. The water separator should be serviced daily.

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The transfer pump draws fuel from the tank and supplies fuel to the injection pump.

The hydraulic head is machined with bores and passages which allow fuel to flow to and from a specific point. For example, fuel flows from the transfer pump to the metering valve or from the metering valve to the inlet passage to the rotor.

The rotor is located in the hydraulic head. The rotor distributes fuel to the delivery valves. The rotor has four inlet passages and one outlet passage. As the rotor turns, fuel enters the passages in the rotor and forces the plungers in the drive end of the rotor outward. As the rotor continues to turn, the inlet passage closes. As the plungers are forced inward by the cam ring and rollers, the fuel pressure in the rotor increases.

At the same time, the outlet passage opens and fuel exits the rotor through the delivery valves to the injectors.

The transfer pressure regulator controls the fuel transfer pressure within the injection pump. Transfer pressure will increase as engine speed increases. The regulator also permits the fuel to bypass the transfer pump when the fuel system is being primed.

The shutoff solenoid allows fuel to enter the fuel injection pump when the solenoid is energized. When the key start switch is moved to the OFF position, the solenoid is de-energized and a spring moves the plunger in the solenoid to block fuel flow.

The metering valve controls the amount of fuel to the hydraulic head or rotor. The valve is connected to a mechanical governor and the throttle or governor control lever. As the metering valve is rotated within the hydraulic head, a delivery control groove in the valve precisely meters fuel to the rotor.

A tapered flat on the metering valve works with the light load valve. The flat is machined in line with the delivery control groove.

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The light load advance valve and metering valve work with two control orifices in the hydraulic head to override the normal speed advance system. During low load conditions, the outward travel of the rollers and shoes is reduced during the rotor filling cycle, which delays the point of roller contact with the cam lobes resulting in retarded injection.

The light load advance compensates for this delay by advancing injection at reduced fuel levels. Passageways are drilled within the hydraulic head body to connect the metering valve "flat" with the pressure end of the advance device (through a second control orifice) and the pump cambox.

As the metering valve is rotated in the hydraulic head by the governor, a larger or smaller flow path from the advance piston to the cambox is created. The relationship between the "flat" with the delivery control groove is arranged so that, as delivery is reduced, flow past the flat is also reduced. Thus, the pressure signal applied to the advance piston is increased to advance the timing.

The boost controller adjusts the maximum fuel delivery based on variations in the boost pressure from the turbocharger. As boost pressure increases, the scroll plates rotate and allow the plunger travel to increase.

This action permits an increase in fuel delivery resulting in more engine horsepower.

The torque trimmer provides a means to regulate the volume of fuel being delivered at full load. The torque trimmer provides the maximum amount of fuel in the loadable range of the engine which can be burned smoke free.

The delivery valves are check valves which open to allow fuel from the pumping mechanism to the injectors. There is one delivery valve per injector. The valves rapidly reduce pressure in the injector lines at the end of the injection cycle to ensure a rapid closure of the injector nozzles and, in conjunction with the cam ring profile, maintain a residual pressure in the fuel lines to the injectors.

The latch valve prevents transfer pressure from reaching the automatic advance mechanism during cranking until the engine is started to prevent premature advance timing.

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The automatic advance mechanism progressively advances the start of injection as engine speed increases. The automatic advance mechanism causes the cam ring to rotate in the pump housing. The spring in the mechanism moves the piston and cam ring to retard the timing, while transfer pressure sensed on the left side of the piston works against the spring to advance the timing.

The check valve prevents reverse fuel flow from the automatic advance due to cam loading. The orifice permits fuel to vent from the automatic advance when the engine rpm are reduced.

The cold advance device is used to reduce white smoke by advancing the engine timing to improve cold idling combustion capability. The cold advance device is sometimes called a "wax motor" and is a relatively slow response actuator.

At start-up, a check valve prevents transfer pressure from flowing to the right end of the automatic advance mechanism preventing the sleeve from moving away from the start advance position. This action prevents the spring from fully retarding the engine timing. After the engine is started and allowed to warm up to a specified temperature, a coolant switch closes and current is sent to the wax motor causing the wax to melt.

As the wax melts, it changes in volume and goes from a solid to a liquid.

After approximately 25 seconds or more, the pin in the device moves to the left and unseats the check valve. Transfer pressure then flows to the right end of the automatic advance mechanism and moves the sleeve to the left against a stop to the normal automatic advance operating mode.

The fuel return check valve maintains a slight pressure in the fuel injection pump to ensure good lubrication. The fuel return check valve also allows hot fuel to bleed from the injection pump for cooling.

NOTE: Only the 430D, 438D and 442D backhoe loaders are equipped with a boost controller.

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The various color codes which are used in this presentation to identify oil flow and pressures for the fuel hydraulic system are as follows: Pink

- Reduced transfer pressure

Red Dots

- Transfer pressure

Red

- High pressure fuel

Blue

- Blocked fuel

Green

- Suction or drain fuel

Purple

- Boost air pressure

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FUEL INJECTION PUMP LOW IDLE STOP

THROTTLE LEVER

HIGH IDLE STOP

METERING VALVE

GOVERNOR SPRING

FUEL SHUTOFF SOLENOID VENT ORIFICE FUEL INLET TRANSFER PRESSURE REGULATOR

FUEL RETURN CHECK VALVE SCROLL LINK PLATE

SCREEN TRANSFER PUMP

DRIVE SHAFT SHIFTER AND SLEEVE

PLUNGERS TO INJECTOR

GOVERNOR FLYWEIGHTS

SHOES SCROLL PLATES

ROLLERS

CAM RING

AUTOMATIC ADVANCE MECHANISM

ORIFICE CHECK VALVE

20 • Fuel injection pump

This illustration shows a sectional view of the fuel injection pump.

Fuel is drawn by the transfer pump through the pressure regulator and sent to the metering valve when the solenoid is energized. The fuel also flows through an annular groove around the rotor to the orifice check valve and the automatic advance mechanism.

The metering valve controls the amount of fuel sent to the pumping elements inside the rotor (plungers, cam ring and shoes). As the rotor turns, the cam ring forces the shoes and plungers in to increase the fuel pressure. The pressurized fuel is then directed to the injectors.

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1 2 4

3 5

6 8 7

9

21

• Fuel injection pump components:

The fuel injection pump is locate on the left side of the engine. Only the 430D, 438D and 442D are equipped with a boost controller (1).

1. Boost controller 2. Fuel shutoff solenoid 3. Fuel transfer pressure regulator and inlet 4. Torque trimmer 5. Latch valve 6. Locking bolt 7. Automatic advance mechanism and cold advance device 8. Delivery valve • Additional engine component: 9. Oil pressure switch

If a new pump is installed on the engine, a locking bolt (6) and a two position spacer in the pump flange below the timing mark on the pump engine flange must be loosened after installing the pump on the engine.

In the locked position, the bolt prevents the pump drive shaft from turning. Move the spacer to provide additional clearance between the bolt head and the pump flange to unlock the pump drive shaft.

If this procedure is not performed, the fuel pump will be damaged if an attempt is made to start the engine. If the timing pin was used this bolt may not have been used to prevent the pump drive shaft from turning.

The oil pressure switch (9) can be removed to install a test nipple to check engine oil pressure.

NOTE: Refer to service manual module "Lucas Fuel Pump Supplement" (Form SENR6525) for more information on removing and installing the fuel injection pump.

This is the same type of fuel pump used on the 914G and IT14G.

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"D" SERIES STARTING AND CHARGING SYSTEM EMISSIONS ENGINE / RUN G

S

MTR

BAT

ACTION LAMP GROUP

101-RD

MOTOR

STARTER

450-YL

309-GY 101-RD

1 2 3 L IG P

TACH.

CBL RD-00 338-PK

B+

ATTACHMENT RELAY

POS NEG

TO FUSES

ALTERNATOR

ALT

POS NEG

COLD START TEMP. SW.

A C

334 BU

327-PK

COLD START ADVANCE SOLENOID

°T

TO RR LIGHTING RELAY TO HVAC RELAY

327-PK

338-PK

CAB RELAY

1 2

A B

A C

TO FUSES

FUEL SHUTDOWN SOLENOID

131-RD

FUSE RELAY BLOCK 2 123-WH

308-YL

TO FUSES 10A TRANSMISSION

15 A THERMAL START AID

MAIN RELAY A C

10A ENGINE FUEL

BATTERY GROUND FORWARD SOL RETURN REVERSE SOL RETURN FORWARD SOL. OUT REVERSE SOL. OUT START RELAY COIL OUT KEY START SW. TO BAT NEUTRALIZER SW. TO BAT PARK BRAKE ALARM OUT PARK BRAKE SW. TO GND. NEUTRAL LOCK SW. TO GND.

1 2 3 4 5 6 7 8 9 10 11 12

310-PU

202-BK

START AID SW.

SHUTTLE CONTROL

THERMAL STARTING AID

R

306-GN START RELAY 20A

304-WH

101-RD

TO FUSES KEY START

307-OR

START RELAY

TO FRONT LIGHTING RELAY

1 2 3 4

C S B

OFF ON ST

KEY START SWITCH

A C

5A 105-RD

FUSE RELAY BLOCK 1

22 ELECTRICAL SYSTEM • Starting system operation: - Batteries - Key start switch to START-RUN - Energize shutdown solenoid - Transmission shuttle control in NEUTRAL - Start relay closes - Energizes starter solenoid

This schematic shows the 12-Volt electrical starting and charging system with the key start switch in the RUN position. From the batteries, power flows to the battery post on the starter, to the fuse relay blocks. From Fuse Relay Block 1, power flows to the key start switch.

When the key is in the START-RUN position and the transmission shift control lever is in NEUTRAL, the start relay is energized through the transmission shuttle control (shift lever). With the start relay closed, power from the battery energizes the starter solenoid and motor. The starter then engages the flywheel ring gear and starts the engine. If the transmission shuttle control is not in NEUTRAL, no power is directed to the start relay, so the engine will not crank.

- Turns starter motor

➥

STMG 746 10/02 • Key start switch in START or RUN: - Fuel shutoff solenoid energized • Key start switch to OFF: - Fuel shutoff solenoid de-energized

- 35 -

When the key is in either the START or RUN position, the fuel shutoff solenoid is energized and allows fuel to flow through the fuel injection pump. Thus, the solenoid is "energized to run."

Turning the key start switch to the OFF position de-energizes the engine shutdown solenoid. The solenoid moves the metering valve linkage to the "fuel off" position.

For cold starts, the start aid switch can be used to energize the thermal starting aid while cranking the engine. When the start aid switch is closed, power to the thermal starting aid heats the coil. Expansion within the coil assembly permits fuel to flow through a check valve when the engine is cranked. The heated fuel becomes a vapor and, as it flows past the coil into the inlet manifold, the fuel is ignited. The ignited fuel heats the inlet air.

When the key start switch is turned to the RUN position or the start aid switch is released, the inlet air cools the coil assembly quickly. The check valve closes and blocks the fuel supply line.

• Charging system operation: - Key start in RUN - Small current excites alternator - Alternator charges batteries and powers accessories - Main relay closed–power to accessories and other relays

The battery is charged by a belt-driven alternator. The alternator is not self-energizing and requires battery voltage to start up.

When the key start switch is in the RUN position, power from the battery goes through the switch to the "IG" terminal of the alternator to excite the alternator field.

With the key start switch in the RUN position, the main relay is closed and power is directed to the accessories and additional relays.

The cold start advance solenoid does not energize until the cold start temperature switch closes.

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2

3 1

23

• Electrical system:

The "D" Series backhoe loaders are equipped with conventional 12-Volt electrical systems with negative ground.

- 12-Volt system - One battery is standard - No disconnect switch

The standard machines are equipped with a 12-Volt maintenance free battery to supply power to the system. The machines can be equipped with two batteries along with a heavy duty alternator for cold weather climates or for use with additional operating lights (attachments).

The system does not have a disconnect switch. To disable the electrical system, remove the battery ground cable from the main frame. The starting system is a key start and stop system.

• Autoshift transmission: 1. Autoshift ECM 2. Diagnostic indicator lamp 3. DT connector

The Autoshift ECM (1) for a machine equipped with an autoshift transmission is also located in the battery compartment.

The diagnostic indicator lamp (2) is used to access active fault information from the control module. The indicator flashes 2-digit fault codes.

The harness connector is a two-pin plug DT connector (3) with an end-termination receptacle.

➥

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During normal operation this plug is installed in the connector. "If a system problem is detected by the transmission control, the diagnostic indicator will turn on and remain on as long as the problem is active."

Turning "on" means the diagnostic indicator will cycle through all flash codes present.

Removing the termination plug from the connector will cause the lamp to flash the first active (low number to high number) two digit fault the transmission control finds. The problem is displayed by blinking the diagnostic indicator. A valid diagnostic code will consist of a series of blinks, (which is the first digit), followed by a short pause, and then a second series of blinks (which is the second digit). If no active problems are present, the control will broadcast diagnostic code "11".

NOTE: Also, located in the battery compartment, but not shown, is a bolt used to manually lower the pilot controlled implements. The bolt provides dead engine lowering capabilities. The bolt should only be used for lowering the loader end and not the backhoe, due to safety concerns.

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1

2 3

24

• Electrical components: 1. Fuse and relay block 1 2. Fuse and relay block 2 3. Diagnostic connector

The fuse and relay blocks (1 and 2) are located below covers on the right side of the cab. The diagnostic connector (3) to connect Electronic Technician (ET) is also shown.

Additional relays (not shown) are located in the side console. Access to these relays is obtained by moving the gauge and switch panel in the side console shown earlier.

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TORQUE CONVERTER HOUSING

FORWARD CLUTCH

IDLER SHAFT REVERSE CLUTCH

PUMP

STANDARD BACKHOE LOADER TRANSMISSION

INPUT SHAFT

COUNTERSHAFT OUTPUT SHAFT

SPEED GEAR AWD SHAFT

SYNCHRONIZER ASSEMBLY

AWD CLUTCH

25 POWER TRAIN • Standard transmission: - Four-speeds - Directional clutches controlled by solenoids

Standard Transmission The standard countershaft transmission is the same as the "C" Series transmission.

The four-speed, direct drive, helical gear, constant mesh, synchronized standard transmission is coupled with hydraulically engaged FORWARD and REVERSE clutches. Each multiple disc clutch pack is controlled by a solenoid valve.

A manually actuated lever and shifter fork arrangement shifts the transmission through the four fully synchronized speed ranges.

➥

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Power is transmitted from the torque converter to the input shaft. If FORWARD is selected, the FORWARD clutch is engaged and power flows from input shaft to the countershaft. The countershaft causes all four speed gears to rotate. A synchronizer will engage one of the speed gears with the output shaft. Power is then directed to the rear axle.

• AWD: - Solenoid controlled clutch - Switch on front console

If the machine is equipped with All Wheel Drive (AWD), a separate shaft and clutch are needed. An additional gear on the output shaft will transmit power to the AWD shaft.

A multiple disc clutch is part of the AWD shaft group. The clutch is hydraulically engaged and spring released. A solenoid controlled valve (not shown) directs oil to pressurize or drain the clutch. The solenoid is connected to a switch on the front console (shown earlier). The front wheel drive axle can be engaged while the vehicle is moving by operating the switch.

INSTRUCTOR NOTE: The various color codes which will be used in this presentation to identify oil flow and pressures for the power train hydraulic system are as follows: Red

- Pump supply or directional clutch pressure

Orange

- Torque converter inlet pressure

Brown

- Lube oil

Green

- Suction or drain oil

STMG 746 10/02

- 41 -

STANDARD POWER TRAIN HYDRAULIC SYSTEM

R

NEUTRAL

FILTER

F RELIEF VALVE DIRECTIONAL SELECTOR SOLENOID VALVE

PUMP SUPPLY PUMP

SUCTION SCREEN

TORQUE CONVERTER INLET

TORQUE CONVERTER INLET RELIEF VALVE

TRANSMISSION LUBE LUBE

OIL COOLER

TORQUE CONVERTER

TORQUE CONVERTER OUTLET

26 • Two Wheel Drive components: - Suction screen - Pump - Oil filter - Directional selector solenoid valve - Relief valve - Torque converter inlet relief valve - Cooler

This illustration shows the power train hydraulic schematic for the standard transmission equipped with Two Wheel Drive.

Oil from the sump is drawn though a suction screen by a crescent-type gear pump located on the transmission input shaft. From the pump, the oil is sent through a spin-on filter to the transmission directional selector solenoid valve.

In NEUTRAL, the oil flow is blocked by the directional selector solenoid valve. Therefore, the oil opens the relief valve and flows to the torque converter. A bypass orifice in the relief valve, is located between the supply circuit and torque converter circuit to make sure that oil is always available to the torque converter when the machine is running.

- Lube circuit

➥

STMG 746 10/02

- 42 -

The torque converter inlet relief valve protects the automotive-type torque converter from high pressure (during cold start-up). Oil from the torque converter goes to the oil cooler, which is located in front of the radiator.

From the cooler, the oil is used for lubrication. A passage directs lube oil to the input shaft of the transmission. Oil from the shaft cools and lubricates the clutch assembly and input shaft bearings. The output shaft, countershaft and reverse idler shaft are splash lubricated. The oil then returns to the sump.

NOTE: The lines and fittings from the torque converter and the oil cooler are sized to provide sufficient restriction to the oil in the torque converter. A torque converter outlet relief valve is not required.

The cold start relief valve between the pump and filter on the "C" Series has been removed on the "D" Series. The valve is no longer required.

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- 43 -

STANDARD POWER TRAIN HYDRAULIC SYSTEM

R

ALL WHEEL DRIVE / FORWARD

FILTER

F RELIEF VALVE AWD SOLENOID VALVE AWD

PUMP SUPPLY PUMP

SUCTION SCREEN

DIRECTIONAL SELECTOR SOLENOID VALVE

TORQUE CONVERTER INLET

TORQUE CONVERTER INLET RELIEF VALVE

TRANSMISSION LUBE LUBE

OIL COOLER

TORQUE CONVERTER

TORQUE CONVERTER OUTLET

27 • AWD components: - AWD solenoid and clutch

This illustration shows the power train hydraulic schematic for the standard transmission equipped with All Wheel Drive (AWD).

The power train hydraulic system for AWD machines is the same as the two wheel drive machines except for an external supply line which directs supply oil to the AWD solenoid valve. When the solenoid is energized, oil engages the AWD clutch.

This schematic shows that the directional selector solenoid valve has been energized. Supply oil flows through the valve to engage the FORWARD clutch. The relief valve limits the maximum clutch pressure.

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- 44 -

AUTOSHIFT TRANSMISSION SOLENOID VALVES

PUMP

INPUT SHAFT

COUNTER SHAFT

OUTPUT SHAFT

AWD SHAFT

28 Autoshift Transmission • Autoshift transmission: - Five-speeds forward, three-speeds reverse transmission - Three speed solenoids - Three directional solenoids

A torque converter (not shown) provides a fluid connection between the engine and the transmission.

The five-speeds forward, three-speeds reverse, autoshift transmission is a constant-mesh, countershaft design. The transmission transfers power to the drive axles. The Autoshift ECM electronically controls the transmission by selectively energizing speed and directional solenoids.

The transmission is equipped with three speed and three directional solenoids. One speed solenoid and one directional solenoid must be simultaneously energized for a transmission gear to be engaged.

Transmissions with the optional AWD system are equipped with an AWD solenoid and an additional output shaft.

NOTE: The reverse shaft and clutch are not shown in this sectional view. It is shown later in this presentation.

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- 45 -

AUTOSHIFT POWER TRAIN HYDRAULIC SYSTEM

DATA LINK SERVICE PORT

NEUTRAL PARKING BRAKE SWITCH

SHIFT LEVER RIDE CONTROL SWITCH

DOWNSHIFT/NEUTRALIZER SWITCH

AUTOSHIFT ECM

AUTO/MANUAL SWITCH NEUTRAL LOCK SWITCH

TRANSMISSION OUTPUT SPEED SENSOR RIDE CONTROL DISABLE

REGULATED PRESSURE

ORIFICE 5

FILTER

6

2

1

3

HI R

2

3

FORWARD

LO

PUMP SUPPLY PUMP SUCTION SCREEN

SOLENOID VALVE

4

RELIEF VALVE

1

TORQUE CONVERTER INLET TORQUE CONVERTER

TRANSMISSION LUBE OIL COOLER

TORQUE CONVERTER OUTLET

LUBE

TORQUE CONVERTER INLET RELIEF VALVE

29 • Autoshift power train hydraulic system in NEUTRAL

This illustration shows the power train hydraulic schematic for the autoshift transmission equipped with Two Wheel Drive.

• Components:

Oil from the sump is drawn though a suction screen by a crescent-type gear pump located on the transmission input shaft. From the pump, the oil is sent through a spin-on filter to the transmission solenoid valves.

- Suction screen - Pump - Oil filter - Solenoid valve - Relief valve - Torque converter inlet relief valve

In NEUTRAL, the oil flow is blocked by the solenoid valves. The supply oil opens the relief valve and flows to the torque converter. A bypass orifice in the relief valve is located between the supply circuit and torque converter circuit to make sure that oil is always available to the torque converter when the machine is running.

- Oil cooler and bypass - Lube circuit - ECM

➥

STMG 746 10/02

- 46 -

The torque converter inlet relief valve protects the automotive-type torque converter from high pressure (during cold start-ups). Oil from the torque converter goes to the oil cooler, which is located in front of the radiator.

An oil cooler bypass valve is used to protect the cooler from excessive pressure caused by cold oil.

From the cooler, the oil is sent to the transmission circuit. A passage directs lube oil to the input shaft of the transmission. Oil from the shaft cools and lubricates the clutch assembly and input shaft bearings. The output shaft, countershaft and reverse idler shaft are splash lubricated.

The oil then returns to the sump.

Orifices in the solenoid valves provide for some clutch modulation when a speed and direction are selected.

• Autoshift ECM

The Autoshift ECM contains the software to control the shifting of the transmission. The software compares the input information to the the information stored in the Autoshift ECM to determine the appropriate gear for the machine.

The Autoshift ECM then sends output signal to energize solenoids for the appropriate clutch. Through ET, FIRST gear can be ENABLED or DISABLED. FIRST gear is a relatively low (slow) gear ratio, and using it may not be necessary for normal loader work or for roading. If using AUTOSHIFT for either loading or roading, disabling FIRST gear eliminates a extra gear shift. In extreme hard digging conditions, the neutralizer button can be used to downshift to FIRST, and then AUTOSHIFT will upshift the transmission as the machine speed increases.

In summary, disabling FIRST makes the tractor more responsive, smoother, and efficient (more productive). Use FIRST gear only when required.

NOTE: The lines and fittings from the torque converter and the oil cooler are sized to provide sufficient restriction to the oil in the torque converter. A torque converter outlet relief valve is not required.

The cold start relief valve between the pump and filter on the "C" Series has been removed on the "D" Series.

STMG 746 10/02

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AUTOSHIFT POWER TRAIN HYDRAULIC SYSTEM

DATA LINK SERVICE PORT

ALL WHEEL DRIVE / SECOND FORWARD NEUTRAL LOCK SWITCH

PARKING BRAKE SWITCH AUTOSHIFT ECM

RIDE CONTROL SWITCH AUTO/MANUAL SWITCH

DOWNSHIFT/NEUTRALIZER SWITCH TRANSMISSION OUTPUT SPEED SENSOR RIDE CONTROL DISABLE

SHIFT LEVER

REGULATED PRESSURE ORIFICE

5

6

2

1

3 AWD

HI R

2

3

FORWARD

LO

SOLENOID VALVE

4

1 RELIEF VALVE

FILTER TORQUE CONVERTER INLET

PUMP SUPPLY TRANSMISSION LUBE

PUMP

OIL COOLER

TORQUE CONVERTER

LUBE

TORQUE CONVERTER OUTLET

SUCTION SCREEN

TORQUE CONVERTER INLET RELIEF VALVE

30

• Autoshift transmission - AWD

Here is the power train hydraulic schematic for the autoshift transmission equipped with All Wheel Drive (AWD).

• SECOND SPEED FORWARD:

The power train hydraulic system for AWD machines is the same as the two wheel drive machines except for the AWD solenoid and clutch.

When the AWD solenoid is energized, oil engages the AWD clutch.

- No. 1 and 4 solenoids energized

This schematic shows the No. 1 and No. 4 solenoids have been energized to engage the forward high directional clutch and the No. 1 speed clutch to obtain SECOND SPEED FORWARD. The relief valve limits the maximum clutch pressure.

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REVERSE

AUTOSHIFT TRANSMISSION FORWARD HIGH

FORWARD LOW

INPUT SHAFT CLUTCH 1

CLUTCH ENGAGEMENT GEAR

FWD LOW

FWD HIGH

5F

X

4F

X

3F

1

X

2F 1F

REV

X X

2

3

SOLENOID

X

1 AND 6

X

1 AND 5

X

3 AND 5

X

1 AND 4

X

3 AND 4

N

COUNTER SHAFT CLUTCH 3

OUTPUT SHAFT AWD CLUTCH

–– CLUTCH 2

1R

X

2R

X

3R

X

X

2 AND 4 X

AWD SHAFT

2 AND 5 X

2 AND 6

31 • Autoshift transmission logic chart

The five-speeds forward, three-speeds reverse transmission is equipped with six clutch packs. The autoshift transmission uses six solenoids to control the engagement of the clutch packs. Two clutch packs must be simultaneously engaged for the transmission to drive the machine. The above chart shows the energized solenoids and the engaged clutch packs for each gear. The solenoids are controlled by the Autoshift ECM. In NEUTRAL, none of the solenoids are energized.

The chart can be used to identify which solenoids are energized to engage the speed and direction clutches to obtain the desired speed range.

NOTE: The Autoshift ECM does not provide shift protection on the "D" Series. Some shift protection is provided for the 446B backhoe loader. Shift protection prevents the operator from changing directions at high speeds.

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AUTOSHIFT ELECTRONIC TRANSMISSION CONTROL SYSTEM FORWARD HIGH No. 1 SOLENOID

CAT DATA LINK KEY START SWITCH

SHIFT LOADER LOCK RELAY

LEVER CONTROL

PARKING BRAKE SWITCH NEUTRAL LOCK SWITCH

BACKUP ALARM

REVERSE No. 2 SOLENOID

RIDE CONTROL SWITCH

START RELAY

TRANSMISSION OUTPUT SPEED SENSOR AUTO/MANUAL SWITCH RIDE CONTROL DISABLE SWITCH

FORWARD LOW No. 3 SOLENOID

AUTOSHIFT ELECTRONIC CONTROL MODULE

SPEED CLUTCH 1 No. 4 SOLENOID SPEED CLUTCH 2 No. 5 SOLENOID SPEED CLUTCH 3 No. 6 SOLENOID PARK BRAKE ALARM RELAY RIDE CONTROL RELAY

DOWNSHIFT/ NEUTRALIZER SWITCH

DIAGNOSTIC INDICATOR and DATA LINK SERVICE PORT

32 • Autoshift ECM operation

The Autoshift ECM has two modes of operation: Automatic and Manual.

In the Automatic Mode of operation, the operator controls the highest desired gear and the transmission control automatically selects the proper gear based on machine ground speed. The transmission determines the ground speed through the transmission speed sensors and energized speed clutch.

In the Manual Mode, the transmission operates very similar to the standard power shift transmission. In this presentation, the Automatic Mode will be discussed except where it is stated that the Manual Mode is being discussed.

➥

STMG 746 10/02

• Shift lever control: - Inputs in Autoshift ECM through Cat Datalink

- 50 -

When the key start switch is ON, the transmission shift lever control provides input to the Autoshift ECM through the CAT Datalink. The Autoshift ECM uses the input from the shift lever control to determine the gear range selected on the transmission shift lever control and the position of the key start switch.

When the key start switch is moved into the START position, the key start switch directs power to the shift lever control. The shift lever control, must be in NEUTRAL to signal the Autoshift ECM that the key start switch is in the START position. The shift lever control completes the circuit between the key start switch and the start relay. The start relay is energized, allowing power to the starter to crank the engine.

If the shift lever control is not in NEUTRAL during starting, the Autoshift ECM will prevent the machine from starting.

• Parking brake switch: - Signals Autoshift ECM - Autoshift ECM prevents transmission from shifting if parking brake ENGAGED

The parking brake switch provides an input signal to the Autoshift ECM. The parking brake switch is closed when the parking brake is ENGAGED and open when the parking brake is RELEASED. If the shift lever control is in NEUTRAL with the parking brake ENGAGED and is then moved out of NEUTRAL, the Autoshift ECM prevents the transmission from shifting and energizes the parking brake relay to sound the alarm.

The Autoshift ECM will allow the transmission to shift when the parking brake is ENGAGED if the shift lever control is cycled into and out of the NEUTRAL position twice within a span of three seconds. If the shift lever control is shifted from NEUTRAL when the parking brake is ENGAGED, the Autoshift ECM records a parking brake event.

When the parking brake is RELEASED and the shift lever control is moved out of the NEUTRAL position, the Autoshift ECM directs output signals to the appropriate transmission control solenoids. The Autoshift ECM energizes one speed and one directional solenoid to engage clutches in the transmission.

➥

STMG 746 10/02

- 51 -

If the parking brake is ENGAGED while the transmission is in a gear, the ECM shifts the transmission into NEUTRAL and energizes the parking brake relay. The transmission will remain in NEUTRAL until the shift lever control is moved into the NEUTRAL position and the parking brake is RELEASED. The shift lever control can then be used to select a gear.

• Transmission neutral lock switch - Neutralizes transmission in LOCK position

• Transmission downshift/neutralizer switch

- Downshift function

The transmission neutral lock switch also provides an input signal to the Autoshift ECM. If the transmission neutral lock switch is moved to the LOCK position, the Autoshift ECM shifts the transmission into NEUTRAL and prevents the transmission from shifting, regardless of the position of the shift lever control. The Autoshift ECM will not shift the transmission until after the shift lever control is moved into the NEUTRAL position and the transmission neutral lock switch is moved to the UNLOCK position.

The transmission is neutralized as soon as the neutralizer/downshift button is pressed. If the button is released within one second, the transmission is downshifted one gear by moving from the neutralized state to the downshifted state. If the button is held for more than one second, the transmission will remain neutralized until the button is released.

When the transmission is downshifted with the downshift function, the transmission control will hold the machine in the downshifted gear for five seconds before the machine returns to the Automatic Mode. The downshift function is implemented by the Neutralizer/Downshift input, which is a dual function input.

When downshifted, with the shifter in the third or fourth position, the Autoshift ECM downshifts the transmission one gear per actuation of the button.

If the operator gives multiple downshift commands, within five seconds, the transmission will be downshifted once in response to the first command. The machine will downshift again if transmission output speed is below runout speed for the next lower gear.

If the machine is above the runout speed for the next lower gear, the transmission control will not downshift until the machine is below the runout speed. If the transmission is in FIRST gear when a downshift command is issued, the command will be ignored.

➥

STMG 746 10/02

- 52 -

If the shift lever is in SECOND, the downshift button will force the machine to be downshifted at once and held in FIRST until a speed or direction change or the five second delay is over.

- Neutralizer function

When a neutralizer request is initiated by the operator, the transmission will momentarily neutralize by de-energizing the direction clutch. Only the directional clutch is de-energized. This will improve shift speed when the button is released and the machine is placed back into gear.

In the Manual Mode, the Downshift/Neutralizer Switch will not permit the transmission to be downshifted.

• Transmission speed sensor: - Provides input to Autoshift ECM - Autoshift ECM uses input to determine downshifts

The transmission speed sensor provides output speed information to the Autoshift ECM. In the Automatic Mode of operation, the operator controls the highest desired gear and the transmission control automatically selects the proper gear based on machine ground speed.

The Autoshift ECM determines the ground speed through the transmission speed sensors and energized speed clutch.

If the machine is in FOURTH, as the ground speed increases, third gear may be skipped as the machine upshifts. This is done through the software to improve shift performance. This feature is called Skip-Shift Logic. In Auto Mode, 3rd gear can be skipped on up-shifts only, allowing the transmission to shift from 2nd to 4th. If the 2nd to 4th shift point is not reached in a specific amount of time (0-1sec) the transmission will shift to 3rd gear. The default mode for the skip-shift is to have the timer value set to zero (disabled). There is a configuration option through ET to allow for enabling of Skip-Shift.

If desired, fifth gear may be enabled or disabled through ET in order to comply with regulations in certain countries.

• Dead engine lower relay

The dead engine lower (loader lock) relay is part of the loader lock valve attachment to control the loader hydraulic lock valves. The input from the loader lock relay is used by the Autoshift ECM to determine if the start relay should be energized. If the loader control lever is in the "FLOAT" position the Autoshift ECM will not allow the machine to start. This action prevents the loader arms from unexpectedly lowering during machine start-up when the machine is equipped with hydraulic lock valves.

NOTE: Fourth gear may also be enabled or disabled through ET.

STMG 746 10/02

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AUTOSHIFT TRANSMISSION 1ST GEAR ENABLED SHIFT LEVER POSITION 4F

GEARS AVAILABLE 1, 2, 3, 4, 5

3F

1, 2, 3

2F

1, 2

1F

1

N 1R

1

2R

1, 2

3R

1, 2, 3

33

• Gear selection in Autoshift (FIRST gear is enabled)

With FIRST gear enabled, the following gears are available in the given conditions.

Shift lever in FIRST: The transmission will be held in FIRST gear.

Shift lever in SECOND: The transmission will automatically shift between FIRST and SECOND in response to machine speed.

Shift lever in THIRD: The transmission will automatically shift between FIRST, SECOND and THIRD in response to machine speed.

The downshift switch can be used to force the transmission into FIRST or SECOND gear.

Shift lever in FOURTH: The transmission will automatically shift between FIRST through FIFTH in response to machine speed. THIRD gear may be skipped by the software. The downshift switch can be used to force the transmission into FIRST, SECOND, THIRD or FOURTH gear.

Whenever a machine is downshifted into a lower gear, the machine maximum gear will be limited to the lower gear for five seconds, then return to normal Automatic Mode.

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AUTOSHIFT TRANSMISSION 1ST GEAR DISABLED SHIFT LEVER POSITION 4F

GEARS AVAILABLE 2, 3, 4, 5

3F

2, 3

2F

2

1F

1

N 1R

1

2R

2

3R

2, 3

34

• Gear selection in Autoshift (FIRST gear is disabled)

With FIRST gear disabled, the following gears are available in the given conditions.

Shift lever in FIRST: The transmission will be held in FIRST. Shift lever in SECOND: The transmission will be held in SECOND unless the operator forces the transmission into FIRST through the downshift switch.

Shift lever in THIRD: The transmission will automatically shift between SECOND and THIRD in response to machine speed. The downshift switch can be used to force the transmission into FIRST or SECOND gear.

Shift lever in FOURTH: The transmission will automatically shift between SECOND through FIFTH in response to machine speed. THIRD gear may be skipped by the software. The downshift switch can be used to force the transmission into FIRST, SECOND, THIRD or FOURTH gear.

If the machine is downshifted into a lower gear, upshifts will be disabled for five seconds, then return to normal Automatic Mode.

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REAR AXLE FIXED RING GEAR

PINION GEAR AND SHAFT

FROM MASTER CYLINDER

DIFFERENTIAL LOCK ACTUATOR DIFFERENTIAL LOCK ASSEMBLY

PLANET GEAR

MULTI-DISC BRAKE ASSEMBLY

BEVEL GEAR

DIFFERENTIAL ASSEMBLY

35 Axles and Brakes • Features: - Hydraulically engaged brakes same as "B" and "C" Series - Differential lock same as "B" and "C" Series

The standard rear axle is similar to the "B" and "C" Series.

Differential lock operation and power flow through the rear axle are the same as with the "B" and "C" Series.

The hydraulically engaged brakes are the same as "B" and "C" Series.

If the machine is equipped with All Wheel Steer, an axle with a limited slip differential is used instead of differential lock.

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BRAKE MASTER CYLINDERS RIGHT BRAKE RELEASED

LEFT BRAKE ENGAGED TO BRAKE PISTON

FROM RESERVOIR

TO BRAKE PISTON SUPPLY PORT

VALVE STEM

PLUNGER

COMPENSATION VALVE

PLUNGER

BRIDGE PIPE PUSH ROD

36 • Brake master cylinders: - Left and right master cylinders the same - Reservoir supplies master cylinder • ENGAGED

This illustration shows the master cylinders. Both the right and left master cylinders are the same. Fluid from the brake fluid reservoir enters each master cylinder through the supply port. Fluid from the reservoir fills the spring chamber and the supply line to the brake piston. The spring and plunger prevent the valve stem from closing the supply port.

When the operator depresses one of the brake pedals, the push rod moves against the plunger. As the plunger moves to the up, trapped oil inside the plunger moves the valve stem up to block the supply port. Fluid pressure in the spring chamber increases. As fluid pressure in the spring chamber increases, the pressure unseats the compensation valve on the left allowing oil to flow to the other master cylinder through the bridge pipe.

➥

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The compensation valve in the right master cylinder blocks the oil in the bridge pipe from entering the right master cylinder. As the plunger continues to move up, it will eventually block the inlet to the compensation valve.

At the same time that oil enters the compensation valve, oil enters the outlet pipe to the brake piston.

As pressure increases behind the brake piston, the piston pushes the discs and plates together against the brake housing to ENGAGE the brake.

If the operator engages both brakes simultaneously, both compensation valves open allowing the pressure in the spring chamber of both master cylinders to equalize.

The distance the operator depresses the brake pedal determines the pressure that the piston exerts on the plates and discs. The farther the operator pushes the brake pedal, the more pressure the piston applies to the plates and discs and, therefore, the greater the braking force.

• RELEASED

When the operator releases the brake pedal, the spring in the master cylinder moves the valve stem away from the inlet port reducing the pressure behind the brake piston. A seal around the piston moves the piston away from the discs and plates to RELEASE the brakes.

• AWS

The same brake valve is used on machines equipped with All Wheel Steer (AWS).

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2

4

1

3

37

• Rear axle components: 1. Hose from master cylinder 2. Differential lock linkage 3. Parking brake disc 4. Parking brake pad assembly

On the rear axle, the hose (1) is connected to the the master cylinder outlet pipes and directs oil to the brake actuator pistons. A bleed screw (not shown) next to the hose allows bleeding of the brake lines.

Mechanical linkage from the parking brake lever engages the caliper and disc-type parking brake (3 and 4). The parking brake is on the drive shaft between the transmission and the rear axle. The parking brake needs to be checked and possibly adjusted at regular intervals.

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1

3

2

38

• Power train components: 1. Brake master cylinders 2. Brake pedals 3. Differential lock pedal

The machine contains two master cylinders (1), one for each brake pedal (2).

The master cylinders can be removed from the machine from inside the operator's compartment. Due to a design change, the brake cylinders no longer have to be removed before removing the cab as required on the "C" Series.

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AWD FRONT AXLE LEFT STEER KNUCKLE HOUSING RING GEAR

KING PINS

BEVEL GEAR

DIFFERENTIAL

PLANET GEAR

SUN GEAR AND SHAFT LEFT DRIVE JOINT

LEFT DRIVE PINION GEAR AXLE AND SHAFT

39 • AWD axle components

The AWD axle is equipped with a conventional bevel and pinion gear differential. The final drive consists of an outboard planetary gear arrangement in each wheel hub.

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1

2 3

40

• AWD front axle: 1. Sealed and lubricated pin 2. Steering cylinder 3. Drain plug

AWD axle is available as an option to replace the standard axle.

The axle is pendulum mounted. The pin (1) is permanently sealed and lubricated. The steering cylinder (2) is mounted to the front of the axle.

The standard axle is also permanently sealed and lubricated. The steering cylinder is mounted to the rear of the axle.

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416D CENTER PIVOT BACKHOE LOADER HYDRAULIC SYSTEM PUMP

TANK END COVER E-STICK COOLER

STICK BUCKET

SMU

BACK FLOW CHECK VALVE

SWING BOOM AUX INLET MANIFOLD

S T E E R

RIGHT STABILIZER LEFT STABILIZER

LEVER

MANIFOLD

LEVER

L I F T

T I L T

A U X

41 STEERING AND IMPLEMENT HYDRAULIC SYSTEMS • 416D hydraulic system: - Center pivot - Mechanical controls

The "D" Series backhoe hydraulic systems incorporate many of the improvements made to late production "C" Series.

The illustration represents the 416D steering and implement hydraulic system.

The steering and implement pump, the pump control and most of the implement control valves function essentially the same. The biggest difference to the implement valves is that on some models they are pilot operated. Also, on some models the operating pressures have also been increased.

On the "D" Series, the stabilizer valves are pilot controlled and are of a different design from previous backhoe loader stabilizer valves.

➥

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The steering system features dynamic signal bleed as did the late production "C" Series. With the dynamic bleed and the steering in HOLD, the steering priority spool bleeds oil through the steering metering unit (SMU) signal line and SMU back to the tank. When the steering wheel is turned, this signal bleed oil shifts the priority spool to direct pump supply oil to the SMU resulting in faster steering response than systems without dynamic bleed.

The hydraulic tank has also been redesigned. An expansion tank is no longer required.

The backflow check valve has been relocated. The valve now restricts return flow from all implement valve groups. On previous backhoes, the valve only worked with the backhoe valve group. The valve assists in preventing cylinder voiding. The check valve does not affect return oil from the SMU. The other major difference in the hydraulic system is the signal network routing, which is referred to as "reverse signal path." The signal network will be described later in this presentation.

NOTE: The colors on the hydraulic schematics and cross-sectional views shown throughout this presentation denote various pressures within the system. The legend of color codes is as follows: Red

- pump supply pressure

Red and white stripes

- reduced pump supply pressure, circuit pressure or load sensing pressure

Red hatch

- further reduced pump supply pressure, circuit pressure or load sensing pressure

Pink

- lowest pump supply pressure, circuit pressure or load sensing pressure

Orange

- signal or pilot pressure

Orange and white stripes - a lower signal or pilot pressure Orange hatch

- further reduced signal pressure

Green

- line open to the tank

Blue

- blocked oil

Yellow

- moving part or active valve envelope.

For metering situations more than one envelope may be highlighted in yellow.

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424D / 428D / 438D SIDE SHIFT BACKHOE LOADERS HYDRAULIC SYSTEM SIDESHIFT LOCK PISTONS PUMP TANK END COVER E-STICK STICK

COOLER

BUCKET BACK FLOW CHECK VALVE

SWING BOOM

SMU

AUX INLET MANIFOLD

S T E E R

SHUTOFF

RIGHT STABILIZER LEFT STABILIZER

LEVER

MANIFOLD

LEVER

L I F T

T I L T

A U X

42 • 424D, 428D and 438D hydraulic system: - Sideshift machines - Mechanical controls

The 424D, 428D and 438D sideshift machines have similar components as the center pivot machines. The sideshift machines are equipped with sideshift lock pistons.

The 424D is not available with two loader bucket tilt cylinders as shown here.

Some countries require a shutoff valve to block the flow of oil to the backhoe valve group when the machine is roaded to prevent unintentional implement movement. Center pivot machines may also be equipped with this feature.

The shutoff valve is an option on those machines with mechanical implement controls only.

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420D / 430D CENTER PIVOT BACKHOE LOADERS HYDRAULIC SYSTEM PARALLEL LIFT PUMP TANK

E-STICK

BUCKET SWING

AUX INLET MANIFOLD

COOLER SMU

BACK FLOW CHECK VALVE

JOYSTICK

BOOM

PATTERN CHANGER

STICK

JOYSTICK

END COVER

JOYSTICK

RIGHT STABILIZER LEFT STABILIZER

LEVER

MANIFOLD

LEVER

S T E E R

PILOT SHUTOFF

L I F T

T I L T

A U X

RIDE CONTROL

43 • 420D and 430D hydraulic system: - Center pivot machines

The backhoe valves on the 420D and 430D are pilot operated. If the machine is equipped with IT linkage, as shown, then the loader valves are also pilot operated. With pilot operated machines a pilot accumulator is used to provide dead engine lowering capability for a limited time after engine shutdown.

- Pilot controls

These machines ship with the excavator control pattern. Machines can be ordered with the standard backhoe control pattern or ordered with an optional pattern changer valve.

If the machine is equipped with the single tilt cylinder bucket, the loader valves are operated through mechanical linkage instead of a pilot joystick.

The pilot shutoff valve blocks the oil from the joysticks to prevent movement of an implement. The shutoff valve eliminates the need of the optional hydraulic shutoff valve available on machines with mechanical controls only.

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432D / 442D SIDESHIFT BACKHOE LOADERS HYDRAULIC SYSTEM PARALLEL LIFT SIDESHIFT LOCK CYLINDERS

PUMP

TANK

E-STICK

BUCKET SWING

AUX INLET MANIFOLD

RIGHT STABILIZER LEFT STABILIZER MANIFOLD

COOLER

SMU

BACK FLOW CHECK VALVE

JOYSTICK

BOOM

PATTERN CHANGER

STICK

JOYSTICK

END COVER

JOYSTICK

S T E E R

LEVER

L I F T

T I L T

A U X

LEVER

PILOT SHUTOFF

RIDE CONTROL

44 • 432D and 442D hydraulic system: - Sideshift machines - Pilot controls

The backhoe valves on the 432D and 442D are pilot operated. The loader valves are also pilot operated since the standard version of these models feature the IT linkage.

The single tilt cylinder bucket is optional. With this option the loader valves are operated through mechanical linkage.

Ride control is an option that is available for all "D" Series backhoes.

Hose routing and the system design has changed from the "C" Series.

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"D" SERIES BACKHOE LOADER SIGNAL NETWORK MECHANICAL CONTROLLED LOADER VALVES PUMP CONTROL VALVE

BACKHOE SECTION AUX

BOOM

SWING

BUCKET

STICK

E-STICK

ORIFICE

TORQUE LIMITER LEFT RIGHT STABILIZER STABILIZER

CONNECTED TO SWASHPLATE LOADER AUX.

LOADER TILT

LOADER LIFT

SMU

PRIMARY RESOLVER SECONDARY RESOLVER LOADER SECTION

45 • Signal network: - Reverse signal path - Affects resolver troubleshooting - Orificed steering resolver - Orifices in loader primary resolvers

On most generations of backhoes, the signal line was routed from the backhoe section, to the loader section and then to the pump. Late production "C" Series had a variation from this with a signal line from the backhoe section and a signal line from the loader section being connected to a tee which was equipped with a resolver. The highest resolved signal between the two valve sections then flows to the pump.

With the "D" Series, the last resolver in the network is in the loader auxiliary circuit. The signal flows from the loader section, to the stabilizer section, to the backhoe section, before going to the pump control valve. This routing is reverse of previous backhoe signal networks.

Resolver troubleshooting procedures are affected by this change. A secondary resolver problem in the loader section will no longer have an affect on the backhoe section.

➥

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The orifice in the steering resolver in the loader section results in a larger pressure differential across each loader resolver orifice when a loader implement is activated and the torque limiter opens, as compared to a backhoe implement. This difference in pressure results in a reduced signal to the torque limiter and pump compensator.

This action provides for lower pump flow to the loader section for a given circuit pressure when the torque limiter opens, which results in a lower available torque for the loader section than what is available for the backhoe section. This change was done to further improve loader and backhoe performance.

Backhoe implements (except for the auxiliary circuits) do not have orifices in their primary resolvers and are not affected by the orifice in the steering resolver.

An additional orifice was added between the backhoe valve section and the orifice in the torque limiter for the "D" Series backhoe to further improve machine performance.

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"D" SERIES BACKHOE LOADER SIGNAL NETWORK PILOT CONTROLLED LOADER VALVES PUMP CONTROL VALVE

BACKHOE SECTION PRIMARY RESOLVER

AUX

BOOM

SWING

BUCKET

STICK

E-STICK

ORIFICE

TORQUE LIMITER CONNECTED TO SWASHPLATE

SECONDARY RESOLVER

LOADER AUX.

LIFT PILOT VALVE

LOADER TILT

LEFT RIGHT STABILIZER STABILIZER LOADER LIFT

SMU

LOADER SECTION PILOT OIL

46 • Signal network: - Pilot operated loader valves

On machines with pilot operated loader valves, the pilot valve for the loader lift circuit is also part of the signal network.

The lift pilot valve directs some pilot oil through the resolver network to upstroke the pump when the loader is in FLOAT. This pilot signal through the signal network causes the pump to increase pump standby pressure to make sure that pilot system pressure remains high enough to hold the lift spool in the FLOAT position.

NOTE: Since the maximum pilot pressure is limited, the pump receives a virtually fixed signal from the pilot system when the lift spool is shifted to FLOAT. This increase in pump supply and signal pressure can be checked at the pump outlet test fitting and the signal test fitting. There is no recommended specification or test for this.

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1 2

4 3

47

• Hydraulic system components: 1. Hydraulic tank 2. Sight gauge 3. Steering Metering Unit (SMU) 4. Drain tube

The hydraulic tank (1) is located between the engine and the cab.

With the relocation of the brake master cylinders, the hydraulic tank was redesigned for increased capacity. With the increase in capacity the overflow or expansion tank is no longer required.

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6

1

3 4

2

5

48

• Hydraulic system components: 1. Hydraulic filter 2. Steering and implement pump 3. Pump control valve 4. Signal pressure test fitting 5. Loader valve group 6. Back flow check valve

• Pump and system tests

In the pump control valve (3) are two spools. The flow compensator (margin spool) regulates output flow in response to the load signal received through the signal network. The flow supplied by the pump will be the amount of flow required to keep supply pressure at a fixed value above the signal pressure. The difference between supply pressure and the signal pressure is called "margin pressure." The flow compensator also controls low pressure standby pressure.

The pressure cutoff spool in the pump control valve limits maximum system pressure and serves as the relief valve for the system.

The back flow check valve (6) is part of the fitting just before the hydraulic filter (1). The check valve helps reduce cylinder cavitation.

Before performing any pump tests or making adjustments to the pump control valve, measure and record the machine cycle times. If the cycle times are within specification, checking low pressure standby or margin pressure may not be required unless the system is overheating. Cycle time checks will also indicate if all or some of the implements in the system are operating within specification.

➥

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This information can be helpful in determining if the pump or the implement is at fault. If all cycle times are too slow, margin pressure and low pressure standby may be set too low. If the machine is too responsive, the margin pressure and low pressure standby may be set too high.

The pump supply pressure test fitting (not shown) can be used to check maximum system pressure or low pressure standby. The fitting can be accessed from below the operator's compartment.

Use the signal pressure test fitting (4) to check the signal pressure or the maximum steering pressure. Signal pressure is compared to pump supply pressure to determine the margin pressure.

All return oil from the implements and steering flows back to the filter through the backflow check valve. Due to the dynamic bleed steering, low pressure standby is over 700 kPa (100 psi) higher than on most "C" Series backhoes.

NOTE: Due to the signal pressure limiter, the steering circuit is commonly used to check margin pressure because the steering circuit pressure is below maximum system pressure.

Engineering is recommending a slightly different procedure for checking margin pressure on "D" machines. The latest recommendation is to lock the boom and move the boom lever about one third travel in the DOWN position.

If Standby Pressure is adjusted to about 3100 kPa (450 psi) or slightly higher, the need to adjust a check margin pressure may not be necessary.

Also, on the "D" Series, engineering is suggesting that circuit and system stall pressures be checked at the signal pressure test fitting.

By doing this the confusion related to checking circuits with lower pressure settings than the pressure cutoff on the pump may be eliminated. For circuits with higher line relief settings than the pressure cutoff, the pressures read at either test port should be the same.

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49

• Hydraulic system components: - Torque limiter (arrow)

A torque limiter (arrow) is used to control the pump. The torque limiter will reduce maximum pump flow available as pressures increase to prevent engine stall.

The torque limiter provides improved hydraulic system performance with less engine horsepower. The torque limiter is adjustable. Before making adjustment to the torque limiter, make sure low idle is set correctly.

NOTE: A quick check to make sure the torque limiter is operating correctly on single tilt cylinder machines, is to operate the machine at low idle. With the machine at normal operating temperatures, apply the service brakes and select SECOND FORWARD. Turn on air conditioner (if equipped) and accessories. Raise and rack back the bucket. If the engine stalls, the torque limiter may need to be adjusted.

For dual tilt cylinder machines, follow the same steps, except stall the bucket in the dump position, instead of racking back.

For more precise adjustment of the torque limiter follow the procedures in the service manual. A torque converter stall test should also be done before adjusting the torque limiter. The engine may not be performing correctly.

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STEERING AND IMPLEMENT PUMP LOW PRESSURE STANDBY / DYNAMIC SIGNAL BLEED

TORQUE LIMITER BLEED SIGNAL

FLOW COMPENSATOR

PUMP OUTPUT

PRESSURE CUTOFF

50 Steering and Implement Pump Operation • LOW PRESSURE STANDBY: - With dynamic signal bleed

With all implements in HOLD, the steering priority valve bleeds some supply oil through a dynamic bleed orifice back to the tank through the SMU. This oil flow creates a low pressure signal which is sensed at the pump compensator.

The LOW PRESSURE STANDBY reading will be higher on "D" Series machines equipped with a dynamic signal bleed steering system than on previous backhoes without this feature.

The spring setting of the torque limiter changes with the angle of the swashplate. As shown here, at minimum angle, the setting is at maximum. As the swashplate angle is increased, the spring setting is reduced.

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SIGNAL

STEERING AND IMPLEMENT PUMP CONSTANT FLOW

PUMP OUTPUT

FLOW COMPENSATOR

PRESSURE CUTOFF

51 • CONSTANT FLOW: - Signal pressure plus spring equals system pressure - Swashplate at constant angle

The pump will UPSTROKE or DESTROKE to match changes in flow requirements.

When pump flow matches system needs the pump supply pressure equals the sum of the load pressure plus the margin spring pressure. The margin spool is in a metering position and the system is stabilized.

CONSTANT FLOW is maintained until there is a change in system flow requirements.

The difference between the signal pressure and the pump supply pressure is the value of the margin spring.

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TORQUE LIMITER CONTROL FLOW COMPENSATOR CONTROL BACKHOE LOADER

FLOW (Q)

PRESSURE (P)

52 • Pressure/Flow (P-Q) Curve: - Sweeping curve shows torque limiter control

This illustration shows a Pressure/Flow (P-Q) Curve Chart for the steering and implement pump. The purpose of the chart is to show how the torque limiter affects the maximum flow rate for the loader and backhoe sections when the torque limiter opens.

The sweeping curves show where the torque limiter has control over the pump flow. The torque limiter destrokes the pump as the system pressure increases. The rate of destroke closely follows the torque curve of the engine.

While on the torque curve, if the system pressure decreases, the torque limiter control will UPSTROKE the pump.

The flow compensator spool regulates pump flow when system pressure and flow requirements are below the curves. This is the area shown in yellow.

➥

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NOTE: When the updated "C" Series was introduced, the torque limiter was being promoted as having "dual settings." This was not the case. The torque limiter has one physical setting. Due to the orifices as discussed earlier, the torque limiter responds as if it had two different settings.

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SIGNAL

STEERING AND IMPLEMENT PUMP TORQUE LIMITER OPEN

TORQUE LIMITER PUMP OUTPUT

FLOW COMPENSATOR

PRESSURE CUTOFF

53 • Torque limiter OPEN: - Pressure setting varies with swashplate angle - Pressure drop across orifice - Reduction in signal pressure to flow compensator

The torque limiter monitors the pump swashplate angle and the pump signal pressure. The pressure setting of the torque limiter varies with the swashplate angle: the greater the swashplate angle, the lower the pressure setting.

For example, if the pump is at full stroke, the torque limiter will begin to destroke the pump when system pressure increases above 15180 kPa (2200 psi). As system pressure continues to increase, the pump flow is further reduced. The allowable pump displacement is inversely proportional to the pump discharge pressure: the higher the pressure, the less pump flow available.

- Pump destrokes - Input torque is maintained

When the torque limiter setting is reached, the torque limiter opens, directing some of the signal oil to the tank. A pressure drop occurs across the orifice, resulting in a slight loss of the actual signal pressure. The flow compensator spool will move up, allowing supply oil to the large actuator piston. The pump will then destroke.

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SIGNAL

STEERING AND IMPLEMENT PUMP TORQUE LIMITER CLOSED

TORQUE LIMITER PUMP OUTPUT

FLOW COMPENSATOR

PRESSURE CUTOFF

54 • Torque limiter OPEN: - Stays open when hydraulic demand at or above torque curve - Two different torque curves

The torque limiter remains open and works with the flow compensator for as long as the conditions for the hydraulic demand are "at" or "above" the torque curve. If the load conditions are demanding a certain pressure, the operator is requesting a certain flow by positioning the valve stem and these conditions are "at" or "above" the torque curve, the torque limiter is open.

In summary, full pump supply pressure is always available. However, flow is regulated to maintain a maximum input torque from the engine.

Due to the additional orifices in the loader resolvers, the torque limiter in effect has two different torque curves: one for the loader and one for the backhoe.

• Torque limiter CLOSED: - Flow compensator controls swashplate

When the hydraulic demand falls below the conditions stated above, the torque limiter closes and the flow compensator then has control over the pump swashplate to regulate pump flow to meet the required system pressure and flow demands.

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4

3 2 1

55

Loader Valve Groups and Steering System • Loader valve group components: 1. Inlet manifold and steering priority valve 2. Loader lift control valve 3. Tilt control valve 4. Auxiliary valve

The loader section consists of an inlet manifold (1) with a steering priority valve, a loader lift control valve (2), a tilt control valve (3) and an optional auxiliary valve (4).

The implement valves shown are pilot operated.

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STEERING PRIORITY VALVE DYNAMIC SIGNAL BLEED FLOW TO IMPLEMENTS

FLOW TO SMU

TO SMU TO TANK

TO SMU TO TANK

DYNAMIC BLEED ORIFICE

DYNAMIC BLEED ORIFICE

PRIORITY SPOOL FROM PREVIOUS VALVE

FROM PREVIOUS VALVE SPRING FROM PUMP

TO LOADER VALVES

SIGNAL PRESSURE LIMITER

TO LOADER VALVES

FROM PUMP

RESOLVER TO SMU

TO SMU TO PUMP

TO PUMP

56 • Steering priority valve operation: - With dynamic signal bleed orifice - Flow to implements

The loader inlet manifold and steering priority valve are shown in two different conditions. One condition shows flow to the implements and the other shows flow to the SMU. Before the engine is started, the spring holds the priority spool to the left.

When the engine is started, the flow from the pump is directed to the priority valve. With the spool to the left, the pump supply oil is directed to the SMU. As the SMU passage fills, oil also enters the axial-drilled hole in the priority spool and flows to the left end of the spool.

As pressure builds on the left end, the spool starts to move to the right, against the force of the spring. The spool begins to restrict the oil flow to the SMU supply passage as the spool continues to move to the right. Oil restricted by the priority spool from entering the SMU supply passage flows to the loader implement valves.

➥

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- 82 -

The priority spool never completely blocks the flow of oil to the SMU supply passage. A small amount of oil is allowed to flow through the dynamic bleed orifice to the priority spool spring cavity where it becomes signal oil.

Signal oil flows from the spring cavity through the SMU signal line to the SMU, where the oil flows to the tank. This action causes the priority spool to meter oil continuously to the SMU supply passage to maintain a predetermined pressure in the SMU supply passage. This pressure provides instantaneous steering response when the steering is activated.

The metering action also reduces spool travel when steering is required, which results in faster steering response.

With all implements in HOLD in this closed-center system, this signal oil is sensed at the pump control valve resulting in an increase in the LOW PRESSURE STANDBY setting.

If flow is not needed for steering and an implement valve in the loader section is activated, the priority valve will direct most of the supply oil to the loader implement circuits.

- Oil flow to SMU

When the steering wheel is turned, more flow is needed at the SMU; this causes a momentary drop in pressure in the SMU supply passage.

Pressure on the left side of the priority spool is also reduced.

The signal bleed pressure oil in the spring cavity and the priority spring move the spool to the left, blocking flow to the implements. As the pump flow increases and supply oil enters the SMU passage, pressure increases in the SMU passage and on the left end of the priority spool. As the forces on both ends of the spool equalize, the spool moves to a position which enables it to maintain the flow requirements of the steering circuit.

As previously stated, the signal oil originates in the priority valve spring cavity. From there, the signal goes to the resolver and to the SMU. At the SMU, the signal line is connected to the pressurized cylinder port (left or right). From the resolver, the signal oil flows to the pump control valve. The pump then increases flow to meet the steering system flow requirements.

Because the priority spool gives preference to the SMU supply circuit, flow may be blocked or metered to the loader implement valves.

➥

STMG 746 10/02 - Signal pressure limiter valve

- 83 -

A signal pressure limiter valve limits the steering signal to protect the various steering components. When the signal pressure reaches a predetermined limit, the poppet in the signal pressure limiter moves to the right, opening a passage to the tank.

The spool moves back to the right and blocks flow from going to the SMU.

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STEERING CIRCUIT TURN

STEERING PRIORITY VALVE

FROM PREVIOUS VALVE

TO LOADER VALVES

MAKEUP VALVE

PUMP SUPPLY

CHECK VALVE TO PUMP COMPENSATOR

STEERING METERING UNIT

57 • Steering circuit: - Signal oil sent to SMU from priority valve - Also enters signal network - SMU directs oil to steering cylinder

• Check valve prevents "kickback" • Makeup valve provides steering capability if the engine stops

This illustration shows the steering system during a TURN. Signal oil is sent from the steering priority valve past the check valve to the SMU where the oil combines with the cylinder oil. The pressure in the SMU signal line is limited to the steering cylinder port pressure. The signal oil also enters the the signal network and flows to the pump control valve.

The pump then increases flow to meet the steering system flow requirements.

Oil from the pump flows past the steering priority valve to the SMU and to the double rod steering cylinder. When the machine makes a TURN, the SMU directs oil to the left side of the cylinder piston and opens the right side to the tank. A TURN in the other direction operates inversely.

The check valve in the pump supply line between the SMU and the loader valve inlet manifold prevents steering "kickback" due to an external force.

The makeup valve provides steering capability when the engine is not running by allowing oil to recirculate between the SMU and the steering cylinder when the steering wheel is turned.

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"D" SERIES MECHANICALLY CONTROLLED LOADER VALVES PUMP

TANK

END COVER E-STICK STICK

COOLER

BUCKET BACKFLOW CHECK VALVE

SWING BOOM

SMU

AUX INLET MANIFOLD

S T E E R

RIGHT STABILIZER LEFT STABILIZER

LEVER

MANIFOLD

LEVER

L I F T

T I L T

A U X

58 • Loader valve operation: - Mechanical controls

The following seven illustrations will cover the remaining valves in the loader valve group that are all mechanically operated.

All of the valves in the loader valve group are closed-center and pressure compensated.

INSTRUCTOR NOTE: Components shown in yellow are shown on block diagrams throughout this presentation. These diagrams are to be used to introduce different sections of the hydraulic system discussed in this presentation.

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LOADER LIFT CONTROL VALVE

FROM PREVIOUS VALVE

HOLD

HEAD END

ROD END

PLUG

ADVANCE SIGNAL PASSAGE TO STEERING VALVE

BALL DETENT FLOW CONTROL VALVE FROM PUMP

59 • Loader lift control valve in HOLD: - Advance signal passage for loader RAISE

The loader lift control valve has a flow control spool and a makeup valve on the rod end work port. The main control spool also has an advance signal passage to help raise the loader.

The loader lift control lever has four positions: RAISE, HOLD, LOWER and FLOAT.

- Four position spool - Mechanical ball detent for FLOAT

INSTRUCTOR NOTE: For a detailed description of implement valve operation used in the "D" Series, refer to STMG 630 "416B 438B Backhoe Loaders–Steering and Implement Hydraulic System" (Form SESV1630).

STMG 746 10/02

- 87 -

FROM PREVIOUS VALVE

416D AND 424D LOADER TILT CONTROL VALVE HOLD

HEAD END

LINE RELIEF AND MAKEUP VALVE

ROD END

TO NEXT VALVE

SOLENOID DETENT ADVANCE SIGNAL PASSAGE

FROM PUMP

FLOW CONTROL VALVE

60 • 416D and 424D tilt control valve in HOLD: - Advance signal passage for RACK BACK - Three position spool - Magnetic detent for "return to dig" feature

The 416D and 424D tilt control valve is used to control a single tilt cylinder.

The tilt control valve has a flow control spool and a pilot operated makeup and line relief valve for each work port. The main control spool has an advance signal passage for the TILT BACK or RACK BACK function.

The control spool has a magnetic detent (solenoid) that is part of the "return to dig" feature.

The loader tilt control lever has three positions: RACK BACK, HOLD and DUMP.

STMG 746 10/02

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428D AND 438D LOADER TILT CONTROL VALVE FOR PARALLEL LIFT HOLD FROM PREVIOUS VALVE ROD END

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO LIFT VALVE

SOLENOID DETENT FLOW CONTROL VALVE FROM PUMP

61 • 428D and 438D tilt valve for parallel lift in HOLD: - Four position spool - Magnetic detent for "return to dig" feature

The 428D and 438D tilt control valve is used to control two tilt cylinders.

The loader parallel tilt control lever has four positions: RACK BACK, HOLD, DUMP and REGENERATIVE DUMP. The valve has a magnetic detent for "return to dig."

STMG 746 10/02

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428D AND 438 LOADER TILT CONTROL VALVE FOR PARALLEL LIFT REGENERATIVE DUMP FROM PREVIOUS VALVE

ROD END

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO LIFT VALVE

SOLENOID DETENT FLOW CONTROL VALVE FROM PUMP

62 • Parallel lift in REGENERATIVE DUMP

The force of gravity tends to cause implements to lower faster than the hydraulic pump and makeup valves can fill the cylinders. A "REGENERATIVE DUMP" position can reduce this tendency.

Due to the lands of the tilt valve, return oil from Port "B" cannot go to the tank. The return oil from the implement is directed through the bridge passage to Port "A" when the control spool is shifted to the REGENERATIVE DUMP position. This position allows the bucket to be powered down by pump flow. This action prevents cylinder cavitation and causes the bucket to dump faster.

NOTE: The line relief valve settings are set lower than maximum system pressure on machines equipped with parallel lift.

STMG 746 10/02

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416D AND 424D AUXILIARY CONTROL VALVE HOLD

LINE RELIEF AND MAKEUP VALVE

PORT A

PORT B

TO NEXT VALVE

FLOW CONTROL VALVE

FROM PUMP

63 • 416D and 424D loader auxiliary control valve in HOLD: - Used for MP bucket

The 416D and 424D loader auxiliary valve is typically used for the MultiPurpose (MP) Bucket.

The loader auxiliary control valve has a flow control spool and a pilot operated makeup and line relief valve for the rod end work port.

- Three position spool

The loader tilt control lever has three positions: OPEN, HOLD and CLOSE.

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428D AND 438D AUXILIARY CONTROL VALVE FOR PARALLEL LIFT HOLD

RESOLVERS

LINE RELIEF AND MAKEUP VALVE

PORT A

PORT B

TO NEXT VALVE

SOLENOID DETENT

CONTROL SPOOL

FLOW CONTROL VALVE

FROM PUMP

64 • 428D and 438D parallel lift loader auxiliary control valve in HOLD: - Three position spool - Line relief and makeup valve

The 428D and 438D loader auxiliary control valve provides more versatility than the 416D and 428D loader auxiliary control valve.

The loader auxiliary control valve has a flow control spool and a pilot operated makeup and line relief valve for the rod end work port.

The auxiliary control lever has three positions.

A solenoid detent is also used for applications requiring continuous flow.

- Solenoid detent

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1

2

65

• Single tilt cylinder loader: 1. Microswitch 2. Loader linkage arm

The loader linkage arm (2) has been redesigned for improved reliability.

The microswitch (1) rides along a cam machined into the bucket link.

The switch works with a solenoid on the bucket control valve to provide the "return to dig" feature.

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"D" SERIES PILOT CONTROLLED LOADER VALVES PUMP TANK

E-STICK

BUCKET SWING

AUX INLET MANIFOLD

COOLER SMU

BACKFLOW CHECK VALVE

JOYSTICK

BOOM

PATTERN CHANGER

STICK

JOYSTICK

END COVER

JOYSTICK

RIGHT STABILIZER LEFT STABILIZER

LEVER

MANIFOLD

LEVER

S T E E R

PILOT SHUTOFF

L I F T

T I L T

A U X

RIDE CONTROL

66 • Loader valve operation: - Pilot controls

The following 14 illustrations will cover the valves in the loader valve group that are pilot operated along with their related components.

The internal components of the pilot controlled implement valve are basically the same as the mechanically controlled implement control valve except for the difference in how the valves are controlled.

All of the valves are closed-center and pressure compensated.

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LOADER LIFT CONTROL VALVE FROM PREVIOUS VALVE

RESOLVERS

HOLD

ADVANCE SIGNAL PASSAGE

ROD END

HEAD END

TO NEXT VALVE

CONTROL SPOOL

PILOT PASSAGE

FLOW CONTROL VALVE

FROM PUMP

67 • Loader lift control valve in HOLD: - Advance signal passage for loader RAISE

The loader lift control valve has a flow control spool and a makeup valve on the rod end work port. The main control spool also has an advance signal passage to help raise the loader.

The loader lift control lever has four positions: RAISE, HOLD, LOWER and FLOAT.

- Four position spool

Pilot oil is directed to either end of the spool to shift the valve.

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LOADER LIFT CONTROL VALVE FROM PREVIOUS VALVE

RESOLVERS

FLOAT

ADVANCE SIGNAL PASSAGE

ROD END

HEAD END TANK PASSAGE

TO NEXT VALVE

CONTROL SPOOL

PILOT PASSAGE

FLOW CONTROL VALVE

FROM PUMP

68 • Loader lift valve in FLOAT

For the FLOAT position, higher pilot pressure acting on the right end of the control spool moves the spool further to the left than for LOWER. Both workports are open to the tank through passages in the valve.

A solenoid in the joystick maintains the spool in FLOAT position until the operator shifts the spool to a different position.

FLOAT is used for "backdragging."

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LOADER TILT CONTROL VALVE FROM PREVIOUS VALVE

HOLD

ROD END

RESOLVERS

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO NEXT VALVE

CONTROL SPOOL

PILOT PASSAGE

FLOW CONTROL VALVE

FROM PUMP

69 • Tilt control valve in HOLD: - Used with dual tilt cylinders - Four position spool

This illustration shows the pilot operated tilt control valve used with the dual tilt cylinder configuration.

The tilt control valve has a flow control spool and a pilot operated makeup and line relief valve for each work port. The main control spool has an advance signal passage for the TILT BACK or RACK BACK function.

The pilot joystick has a magnetic detent (solenoid) that is part of the "return to dig" feature.

The loader tilt control lever has four positions: RACK BACK, HOLD, DUMP and REGENERATIVE DUMP.

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LOADER TILT CONTROL VALVE FROM PREVIOUS VALVE

REGENERATIVE DUMP

PORT A

RESOLVERS

PORT B LINE RELIEF AND MAKEUP VALVE

TO NEXT VALVE

CONTROL SPOOL

PILOT PASSAGE FLOW CONTROL VALVE

FROM PUMP

70 • Parallel lift in REGENERATIVE DUMP

The force of gravity tends to cause implements to lower faster than the hydraulic pump and makeup valves can fill the cylinders. A "REGENERATIVE DUMP" position can reduce this tendency.

Due to the lands of the tilt valve, return oil from Port "B" cannot go to the tank. The return oil from the implement is instead directed through the bridge passage to Port "A" when the control spool is shifted to the REGENERATIVE DUMP position.

This position allows the bucket to be powered down by pump flow. This action prevents cylinder cavitation and causes the bucket to dump faster.

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LOADER AUXILIARY CONTROL VALVE FROM LOADER JOYSTICK

RESOLVERS

HOLD

LINE RELIEF AND MAKEUP VALVE

PORT A

PORT B

CONTROL SPOOL TO NEXT VALVE

AUXILIARY HYDRAULIC SOLENOID VALVE NO. 2

FLOW CONTROL VALVE

FROM PUMP

AUXILIARY HYDRAULIC SOLENOID VALVE NO. 1

71 • Loader auxiliary control valve in HOLD: - Solenoids controlled by the Auxiliary Control Module (ECM)

The loader auxiliary control valve is equipped with two proportional solenoids.

The solenoids direct pilot oil to shift the control spool. The solenoids are controlled by the Auxiliary Control Module (ECM).

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LOADER AUXILIARY CONTROL VALVE

FROM LOADER JOYSTICK

HOLD

RESOLVERS

PORT A

LINE RELIEF AND MAKEUP VALVE

PORT B

CONTROL SPOOL AUXILIARY HYDRAULIC SOLENOID NO. 1

TO NEXT VALVE

AUXILIARY HYDRAULIC SOLENOID NO. 2

REVERSE DIRECTION DISABLE JUMPER

FROM PUMP

FLOW CONTROL VALVE E540 PK

E540 PK

E544 GN

E543 WH

PILOT OIL FROM END COVER

TO KEY SWITCH

G943 BU

QUICK COUPLER SWITCH 1 2 3 5

4 6

JOYSTICK

163 WH N997 WH

AUXILIARY CONTROL ECM

203 BK 585 YL

203 BK

PILOT LOADER HANDLE CONTROL

586 BR M968 BU H833 PU 779 WH 163 WH

CONTINUOUS FLOW SWITCH

QUICK COUPLER SOLENOID VALVE

TO KEY SWITCH

72 • Loader auxiliary circuit: - Quick coupler switch

The Auxiliary Control ECM receives inputs from the thumb switch on the joystick, the continuous flow switch and the quick coupler switch.

- Continuous flow switch

The Auxiliary Control ECM senses the position of the quick coupler switch to control the quick coupler solenoid valve. The solenoid valve locks or unlocks the coupler pins.

- Quick coupler solenoid valve

A manual diverter valve (not shown) mounted on the loader linkage allows oil to and from the coupler pins or to and from an auxiliary circuit.

- Auxiliary Control ECM

When the coupler pins are unlocked, the coupler pins can be engaged or disengaged with the quick coupler switch. The thumb switch can be used to engage the pins.

- Auxiliary hydraulic solenoids

When the coupler switch is moved to the LOCKED position, the Auxiliary Control ECM will de-energize the quick coupler solenoid valve.

The coupler pins are then locked in position.

STMG 746 10/02

- 100 -

LOADER AUXILIARY CONTROL VALVE

FROM LOADER JOYSTICK

SHIFT

RESOLVERS

PORT A

LINE RELIEF AND MAKEUP VALVE

PORT B

CONTROL SPOOL AUXILIARY HYDRAULIC SOLENOID NO. 1

TO NEXT VALVE

AUXILIARY HYDRAULIC SOLENOID NO. 2

FROM PUMP

FLOW CONTROL VALVE E540 PK

E540 PK E543 WH

E544 GN

REVERSE DIRECTION DISABLE JUMPER

PILOT OIL FROM END COVER

TO KEY SWITCH

JOYSTICK

G943 BU 163 WH

QUICK COUPLER SWITCH

1 2 3 5

4 6

N997 WH

AUXILIARY CONTROL ECM

203 BK 585 YL

203 BK

PILOT LOADER HANDLE CONTROL

586 BR M968 BU H833 PU

779 WH 163 WH

CONTINUOUS FLOW SWITCH

QUICK COUPLER SOLENOID VALVE

TO KEY SWITCH

73 • Loader auxiliary circuit: - Auxiliary Control ECM sensed thumb switch position to control auxiliary solenoid - Continuous flow switch used to maintain flow rate - Reverse direction disable jumper

When the thumb switch on the joystick is moved, the Auxiliary Control ECM senses the position of the thumb switch and send a variable current to one of the proportional solenoids to shift the auxiliary control spool.

The current will vary depending on how far the thumb switch is moved.

The solenoid directs pilot oil to one end of the control spool.

Operation of the flow control spool and resolvers is the same as with other pressure compensated implement control valves used on backhoe loaders.

If the operator wants to maintain a fixed flow rate, the continuous flow switch can be pressed momentarily. Then release the thumb switch within one second. When the thumb switch is released, the desired flow rate will be maintained until either the thumb switch is moved, the continuous flow switch is pressed again or the quick coupler switch is activated.

For some attachments (broom), the reverse direction disable jumper is installed to disable solenoid No. 1. The auxiliary circuit will now only operate in one direction.

STMG 746 10/02

- 101 -

3

2

1

74

• Loader pilot controls: 1. Pilot joystick 2. Buttons 3. Thumb switch

On the loader pilot joystick (1), the yellow buttons (2) on the control can be used to control an auxiliary function or for AWS. On the electrical schematic the buttons control the left and right broom angle relays.

The thumb switch (3) works with a the Auxiliary Control ECM to vary the current to two proportional solenoids mounted on the loader auxiliary valve. A switch on the front of the joystick is used to downshift the transmission or neutralize it depending on how long the switch is held.

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75

• Auxiliary Control ECM (arrow)

The Auxiliary Control ECM (arrow) is located below the side console gauge and switch panel.

If the machine is equipped with the optional Machine Security System (MSS), the ECM for MSS is attached to the back of the Auxiliary Control ECM.

STMG 746 10/02

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3

2 1

76

• Loader components: 1. Coupler cylinder guard 2. Diverter valve lever 3. Reverse direction disable harness connector

The diverter valve lever (2) allows the operator to divert flow to an attachment and blocks the oil in the coupler cylinder to lock the attachment to the loader linkage. The cylinder is protected by a guard (1).

The reverse direction disable harness connector (3) permits connecting a jumper to disable the No. 1 auxiliary solenoid to allow flow in only one direction.

When the jumper (not shown) is installed, the thumb switch on the loader joystick only operates an attachment in one direction.

An additional harness connector (not shown) allows the connection of an electrically controlled function to the front loader. This function is controlled by the two yellow buttons shown earlier on the loader joystick.

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- 104 -

ACCUMULATOR

ORIFICE

975-WH F748-WH

RIDE CONTROL SWITCH 614-PU

1 2 3 4 5 6

SHUTOFF VALVE

A972-OR 976-OR F739-GN E701-PK

RIDE CONTROL RELAY M969-YL

1 2 134-YL

ORIFICE

PUMP SUPPLY

1 2

SOLENOID

ARC SUPPRESSION

LIFT CYLINDERS

CHECK VALVE

LIFT CONTROL VALVE PUMP SUPPLY

F738-WH

PRESSURE SWITCH FLOW COMPENSATOR

RIDE CONTROL STANDARD TRANSMISSION ON SIGNAL FROM PREVIOUS VALVE TO TANK RESOLVERS

77 • Ride Control System: - Standard transmission

• Ride control switch ON: - Circuit grounded through closed pressure switch - Pressure switch senses rod end pressure

This illustration shows a combined electrical/hydraulic schematic of the Ride Control System on machines with a standard transmission. The lift control valve is in HOLD and is blocking both the rod and head ends of the cylinder.

When the key start switch is in the ON position, power is available at the ride control switch through the 614-PU wire and the switch and dash indicators are illuminated. When the ride control switch is in the OFF position, the ride control solenoid is not energized.

To energize the coil in the ride control relay the pressure switch must be closed to complete the circuit from the ride control switch.

The pressure switch senses the pressure in the line to the rod end of the loader lift cylinder. When the pressure in the rod end of the loader lift cylinder is less than the actuation pressure of the pressure switch, the switch closes.

➥

STMG 746 10/02 - Low pressure, switch closes - Relay closes - Ride control solenoid energized

• Ride control ON: - Accumulator and cylinder head ends connected - Accumulator acts as shock absorber over rough terrain • Ride control OFF: - Solenoid not energized - Orifice creates restriction between accumulator and cylinders - Prevents rapid loss of stored oil - Allows accumulator to be recharged • Pressure switch - Prevents ride control from being activated if pressure high

- 105 -

When the pressure switch is closed, the coil in the relay is energized, closing the relay. Power from the ride control switch flows through the ride control relay to the solenoid. The ride control solenoid is now energized.

When the ride control solenoid is energized, pump supply oil flows through the solenoid to unseat the check valve and to shift the shut-off valve. This action connects the head end of the loader lift cylinders to the ride control accumulator and the rod end of the loader lift cylinders are open to the tank through the check valve.

When the machine is driven over rough terrain with the ride control system ON, the loader lift cylinders extend and retract. As the lift cylinders extend, oil displaced from the rod ends of the cylinders open to the tank and oil which is stored in the accumulator flows into the head ends of the cylinders. As the lift cylinders retract, oil displaced from the head ends of the cylinders flows into the accumulator, and oil is drawn from the tank into the rod ends of the cylinders. The accumulator acts as a shock absorber when the cylinders retract, providing a smoother ride.

When the ride control system is OFF, the ride control solenoid is not energized. Under this condition, the solenoid drains the supply oil to the check valve and the shutoff valve to the tank. The check valve seats and blocks the passage from the rod ends of the lift cylinders to the tank. The shut-off valve moves down and blocks the flow of oil through it. The orifice dampens the closing of the check valve and the shifting of the shut-off valve.

The orifice in the line between the accumulator and cylinder head ends prevents the rapid loss of the oil which is stored in the accumulator when the loader arms are lowered. The orifice also allows the accumulator to be charged, without adversely affecting machine performance when the loader arms are lifted.

The pressure switch prevents the ride control relay, and therefore, the ride control solenoid, from energizing if the pressure in the rod end of the loader lift cylinder becomes greater than the actuation pressure of the pressure switch. An example of this situation is when the loader arms are used to lift the front wheels off of the ground. If the ride control system was engaged under this circumstance, the machine would fall to the ground.

STMG 746 10/02

- 106 -

AUTOSHIFT ECM 123-WH

F748-WH

RIDE CONTROL SWITCH 614-PU

1 2 3 4 5 6

ACCUMULATOR

1 2

BATTERY GROUND

21 22 39 37 23 18

R/C AUTO SW TO GND R/C ON SW TO GND SOL RETURN RIDE CNTRL RELAY PRESS SW TO GND R/C ENABLE CMD SW TO BAT

SHUTOFF VALVE

E702-OR 1 2

975-WH F739-GN

A972-OR

976-OR

E701-PK

M969-YL

1 2

RIDE CONTROL RELAY

PUMP SUPPLY

134-YL 1 2

ARC SUPPRESSION

SOLENOID

LIFT CYLINDERS

CHECK VALVE

LIFT CONTROL VALVE PUMP SUPPLY

F738-WH

PRESSURE SWITCH FLOW COMPENSATOR

RIDE CONTROL AUTOSHIFT TRANSMISSION AUTO MODE ON SIGNAL FROM PREVIOUS VALVE TO TANK RESOLVERS

78 • Ride Control System: - Power shift transmission

The Ride Control System on machines with the optional autoshift transmission use the Autoshift ECM. The Autoshift ECM monitors the position of the ride control switch and determines when to operate the ride control system.

The ride control switch is a three position switch: OFF, ON and AUTO. When the key start switch is in the ON position, power is available at the ride control switch through the 614-PU wire and at the Autoshift ECM through the 123-WH wire. The Autoshift ECM monitors the ride control switch position at terminals 21 and 22. When the ride control switch is in the OFF position, the circuits at terminals 21 and 22 of the Autoshift ECM are open.

➥

STMG 746 10/02

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When the ride control switch is in the ON position, power transfers to the ride control relay. Power available at the ride control switch illuminates the indicators in the switch and the ride control indicator on the instrument panel.

• Ride control switch ON: - If Autoshift ECM senses: - Circuit at terminal 22 closed - Pressure switch closed - Then ride control relay closes: - Ride control solenoid energized

With the ride control switch closed, the Autoshift ECM reads a closed circuit at terminal 22 (Ride Control ON). This closed circuit confirms to the Autoshift ECM that the ride control switch is in the ON position.

Before the Autoshift ECM will create an output signal to energize the ride control solenoid, the condition of the pressure switch which is located in the rod end of the loader lift cylinder must be determined. The pressure switch senses rod end cylinder pressure. If the rod end pressure is below the actuation setting of the switch, the switch is closed and the Autoshift ECM will send a signal to close the ride control relay. When the relay closes the solenoid is energized. If the pressure is too high the switch is open and the Autoshift ECM will not send a signal to the relay.

When the ride control solenoid is energized, pump supply oil flows through the solenoid to unseat the check valve and to shift the shut-off valve. This action connects the head end of the loader lift cylinders to the ride control accumulator, and the rod end of the loader lift cylinders are open to the tank through the check valve.

• Ride control switch AUTO:

When the ride control switch is in the AUTO position the Autoshift ECM reads a closed circuit at terminal 21.

- If Autoshift ECM senses:

A closed circuit at terminal 21 confirms to the Autoshift ECM that the ride control switch is in the AUTO position. Under this condition, the Autoshift ECM uses input from the pressure switch and the speed sensor to determine when to operate the ride control system.

- Circuit at terminal 21 closed - Pressure switch closed - Sufficient ground speed - Then ride control relay closes: - Ride control solenoid energized

If the speed sensor input indicates ground speed is less than approximately 9.5 kilometers per hour (6 mph), the Autoshift ECM will not engage the ride control system. If the input indicates that the ground speed is greater than approximately 9.5 kilometers per hour (6 mph), the Autoshift ECM directs an output signal to close the ride control relay.

When the relay closes the solenoid is energized.

NOTE: ET can be used to adjust the speed at which the Autoshift ECM engages Ride Control.

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3 2

1

79

• Ride Control System components: 1. Ride control valve 2. Accumulator 3. Guard

The ride control valve (1) is located on the inside of the right frame rail below the cab.

The accumulator (2) is protected by a guard (3).

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- 109 -

DEAD ENGINE LOWER CIRCUIT SOLENOIDS ENERGIZED CONN. 19 1 2 BK-18 3 4

GN-18 BK-18 PK-18 PK-18

CONN. 19 1 2 3 4

85 87

86 30

BK-18

87A

87

86 30

BK-18

YL-18

87A DEAD ENG LOWER COMMAND RELAY YL-18

GN-18

CONN. 12 1 2 3 4

CONN. 12

YL-18

BU-18 BK-18 YL-18 OR-18

1 2 3 4

BK-18 YL-18 GN-18

1 2 3 4 5 6

1 2

GN-18

A B C

BU-18 RD-18 BK-18

8 1

3 5 MOM 4 6

CONN. 56

RD-18 BR-18 RH LOCK VALVE SOL.

BK-18 GN-18 BK-18

2

WH-18 OR-18 PK-18 GN-18 BK-18 YL-18

RD-18 BR-18 LH LOCK VALVE SOL.

GN-18 WH-18 BK-18 PK-18 OR-18 1 DEAD ENG. LOWER SW. 2 OR-18 OR-18 YL-18 BK-18

BK-18

1 2

YL-18 GN-18

YL-18 GN-18

1 2 3 4

1 YL-18 2 GN-18 DEL. ARC SUPPR. 1 1 YL-18 2 GN-18 DEL. ARC SUPPR. 2 PU-18 PU-18 PU-18 7 BK-18

DEAD ENG. LOWER ENABLE RELAY BK-18 85

CONN. 57 YL-18 BK-18 GN-18 BK-18

BK-18

A B C 7 MOM

FLOAT DETENT LIMIT SW. BU-18 RD-18 BK-18 8 1

2 MOM

3 4

5

6

FLOAT DETENT PILOT PRESS. SW.

DUAL FUNCTION RIDE CONTROL SWITCH

80 • Dead engine lower with loader lock valves

Some machines may be equipped with optional loader lock solenoid valves.

For these machines a dead engine lower switch is required to energize the solenoids to allow the operator to lower the loader arms with a dead engine.

The dual function ride control switch is used with machines equipped with ride control and the loader lock valves. When ride control is activated the lock valves solenoids are energized to allow ride control to work.

STMG 746 10/02

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"D" SERIES MECHANICALLY CONTROLLED BACKHOE VALVES SIDESHIFT LOCK PISTONS PUMP

TANK

END COVER E-STICK STICK

COOLER

BUCKET BACK FLOW CHECK VALVE

SWING BOOM

SMU

AUX INLET MANIFOLD

S T E E R

RIGHT STABILIZER LEFT STABILIZER

LEVER

MANIFOLD

LEVER

L I F T

T I L T

A U X

81 Backhoe Valve Groups • Backhoe valve group: - Mechanically controlled

The following seven illustrations will cover the valves in the backhoe valve group that are mechanically operated.

All of the valves are closed-center. Only the swing, E-stick and auxiliary valves are pressure compensated.

STMG 746 10/02

FROM PREVIOUS VALVE

- 111 -

BACKHOE AUXILIARY CONTROL VALVE HOLD PORT A

PORT B

PLUG

TO NEXT VALVE

FROM PUMP

FLOW CONTROL VALVE

82 • Backhoe auxiliary control valve in HOLD: - Pressure compensated - Three position spool

The auxiliary valve shown here is used for the extendible stick or can be used for other backhoe attachments.

These valves are controlled by foot pedals and are found in both the mechanical operated backhoe valve group and in the pilot operated backhoe valve group.

The major components of these optional valves are the same as those in the auxiliary valve in the loader section, except these valves do not have a pilot operated line relief and makeup valve.

STMG 746 10/02

- 112 -

STICK CONTROL VALVE FROM PREVIOUS VALVE

HOLD

RESOLVERS

LINE RELIEF VALVE

ROD END

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO NEXT VALVE

CONTROL SPOOL

LOAD CHECK VALVE

FROM PUMP

83 • Stick control valve in HOLD: - Mechanically controlled

The stick control valve is equipped with a line relief valve for the rod end and a combination line relief and makeup valve for the head end. The valve is not pressure compensated.

The load check valve is not the same as used on the "C" Series. The load check valve still serves the same function of preventing implement drift until system pressure increases to move the spool to the left to provide flow to the cylinder.

Due to improved control spool design, an advance signal passage is no longer required for STICK OUT.

STMG 746 10/02

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STICK CONTROL VALVE

FROM PREVIOUS VALVE

STICK OUT

RESOLVERS

LINE RELIEF VALVE

ROD END

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO NEXT VALVE

CONTROL SPOOL

LOAD CHECK VALVE

FROM PUMP

84 • Stick control valve in STICK OUT

When an implement is activated and supply pressure is higher than cylinder pressure, the check valve is pushed to the left. Oil can then flow to the cylinder.

As long as the system pressure is higher than the work port pressure, the load check valve will stay to the right.

STMG 746 10/02

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BUCKET CONTROL VALVE FROM PREVIOUS VALVE

HOLD

ROD END

RESOLVERS

HEAD END

LINE RELIEF

TO NEXT VALVE

CONTROL SPOOL

FROM PUMP

LOAD CHECK VALVE

85 • Bucket control valve in HOLD: - Mechanically controlled

The bucket control valve contains line relief valves for the rod end and the head end of the cylinder. The valve is not pressure compensated.

STMG 746 10/02

- 115 -

FROM PREVIOUS VALVE

RESOLVERS

SWING CONTROL VALVE HOLD

ADVANCE SIGNAL PASSAGE

SWING LEFT

SWING RIGHT

CHECK VALVE

LINE RELIEF VALVE

SIGNAL METERING SLOT

TO NEXT VALVE

CONTROL SPOOL

FLOW CONTROL VALVE

FROM PUMP

86 • Swing control valve in HOLD: - Signal metering slots improve modulation

• Check valves: - Maintain pressure on cylinder pistons in hold - Reduce swing "wag"

To improve swing modulation, advance signal metering slots are machined in the main control spool.

Inside the main control spool are two check valves. The spool also has advance signal passages. Inside the flow control spool is a load check valve which prevents swing drift.

The check valves allow the system to maintain pressure on the cylinder pistons in HOLD. Due to the check valves, the main control spool is no longer a true closed-center control valve.

By maintaining a pressure on both sides of the cylinder pistons during a swing, the amount of swing "wag" is reduced when the swing lever is returned to HOLD. The check valves will also act as makeup valves to prevent cylinder voiding.

➥

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When the engine is not running, the springs (only one spring shown for clarity) at the left end of the flow control spool shift the spool to the right.

The flow control valve is in a parallel circuit and has equal access to pump supply oil. When the engine is started, supply oil to the flow control spool enters the passage in the center of the spool and fills the chamber at the right end of the spool. As pressure increases on the right end of the flow control spool, the spool moves to the left against the springs. Supply oil then flows to the main control spool where a small amount of oil flows past both check valves in the main control spool and enters both work ports. The oil is then blocked by the cylinder pistons.

This action maintains pressure on both ends of each piston.

As the flow control spool moves to the left, the metering slots in the flow control spool begin to close creating a restriction to the pump supply oil.

Because of the restriction, pressure in the work ports and on the right end of the flow control spool is reduced. The pressure on the right end of the flow control spool, which is limited by the flow control springs, is the same as the pressure in the work ports. This pressure of 415 kPa (60 psi) is maintained in the work ports to improve the implement response when the main control spool is shifted.

• Advance signal operation

When the spool is initially shifted, the advance signal passage sends some pump supply oil to the signal cavity before oil is directed to the cylinders.

The signal is then sent back to the pump control valve to upstroke the pump. The signal metering slots meter some of this signal pressure to the tank, thus preventing the pump from going to a "high pressure standby" mode.

The signal metering slots provide more benefit to the operator when the spool is returned to the HOLD position. The slots meter the signal pressure to the tank and dampen the shock created by closing the spool.

Operation of the swing is smoother and swing "wag" is further reduced.

The signal metering slots also provide improved start-up metering.

NOTE: A signal limiter was shown in the first verion of this Service Training Meeting Guide and other service literature. The limiter was removed just prior to first ship and is no longer used on the swing circuit for any "D" Series machine.

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FROM PREVIOUS VALVE

RESOLVERS

SWING CONTROL VALVE SWING RIGHT SWING LEFT ADVANCE SIGNAL PASSAGE

SWING RIGHT

CHECK LINE RELIEF VALVE VALVE

SIGNAL METERING SLOT

TO NEXT VALVE

CONTROL SPOOL

FROM PUMP

FLOW CONTROL VALVE

87 • Swing RIGHT: - Supply oil unseats left check valve - Return oil unseats left check valve - Left check valve provides a pressurized swing

When the spool is shifted to SWING RIGHT, the work port pressure is sent through the signal network and to the flow control valve. Supply oil enters the main control spool and unseats the check valve on the right.

Return oil from the swing right work port also enters the spool, unseats the right check valve, and flows to the tank. The left check valve creates a back pressure on the oil returning to the tank to provide a pressurized swing.

Pressure oil on the right end of the flow control valve will work against the signal oil and springs on the left end of the flow control valve to maintain the desired flow rate to the swing circuit.

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428D / 438D BOOM CONTROL VALVE FROM PREVIOUS VALVE

RESOLVERS

HOLD

ROD END

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO NEXT VALVE

CONTROL SPOOL

LOAD CHECK VALVE

FROM PUMP

88 • Boom control valve in HOLD: - Mechanically controlled

The boom control valve contains combination line relief and makeup valves for the head end and rod end of the cylinder.

The valve is not pressure compensated. The load check valve prevents implement drift whenever a circuit is first activated or due to lack of flow, the system pressure is less than needed to support or move the load.

Due to improved control spool design, an advance signal passage is no longer required for BOOM-UP on the 428D and 438D. On the 416D and 424D an advance signal passage is required.

NOTE: Due to the improved line routings, the head end and rod end workports have been reversed on the "D" Series from the "C" Series on the boom and stick circuits.

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"D" SERIES PILOT CONTROLLED BACKHOE VALVES AND STABILIZER VALVES SIDESHIFT LOCK CYLINDERS

PUMP

TANK

E-STICK

BUCKET SWING

AUX INLET MANIFOLD

RIGHT STABILIZER LEFT STABILIZER MANIFOLD

COOLER

SMU

BACK FLOW CHECK VALVE

JOYSTICK

BOOM

PATTERN CHANGER

STICK

JOYSTICK

END COVER

JOYSTICK

S T E E R

LEVER LEVER

PILOT SHUTOFF

L I F T

T I L T

A U X

RIDE CONTROL

89 • Pilot operated backhoe valve group

The following 12 illustrations are related to the pilot operated backhoe section valves, stabilizer valves and sideshift frame.

• Stabilizer valves

All of the valves are closed-center. Only the swing, E-stick and auxiliary valves are pressure compensated.

• Sideshift frame

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5 1

2

4 3

90

• Backhoe valve group: 1. Boom 2. Swing 3. Bucket 4. Stick 5. E-Stick

This illustration shows the pilot operated backhoe valve group located at the rear of the machine. Outlet ports to the cylinders face the rear of the machine on all models. This change from the "C" Series resulted in improved line routing.

The valve group can have up to six valve sections.

Access to the secondary resolvers on center pivot machines must be done from below the machine instead of at the rear of the machine as was done on former backhoes.

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3 1

2

91

• Hydraulic components: 1. Optional pattern changeover valve

The optional pattern changeover valve (1) for the pilot operated backhoe valve group is mounted on the right side of the rear frame.

The valve allows the operator to change from the excavator pattern to the backhoe pattern.

2. Pilot shutoff valve 3. Pilot return manifold

Machines equipped with pilot hydraulics are equipped with a backhoe shutoff switch on the side console. The switch controls the pilot shutoff solenoid valve (2) that is mounted on the front of the rear axle.

The solenoid, when energized, allows pilot oil to flow to the joysticks.

When the solenoid is de-energized the joysticks are disabled.

To lower implements with a dead engine, the key start switch must be turned to the ON position.

NOTE: The axles on the "D" Series no longer feature brake disc inspection ports.

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STICK CONTROL VALVE FROM PREVIOUS VALVE

RESOLVERS

HOLD

LINE RELIEF VALVE

ROD END

TO NEXT VALVE

HEAD END

LINE RELIEF AND MAKEUP VALVE

CONTROL SPOOL

LOAD CHECK VALVE

PILOT PASSAGE

FROM PUMP

92 • Stick control valve in HOLD: - Pilot operated

The stick control valve is equipped with a line relief valve for the rod end and a combination line relief and makeup valve for the head end. The valve is not pressure compensated.

Except for being pilot controlled, the valve operation is the same as the mechanically controlled stick control valve.

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BUCKET CONTROL VALVE

FROM PREVIOUS VALVE

HOLD

RESOLVERS

TO NEXT VALVE

ROD END

HEAD END

LINE RELIEF VALVE

CONTROL SPOOL

PILOT PASSAGE

LOAD CHECK VALVE

FROM PUMP

93 • Bucket control valve in HOLD: - Pilot operated

The bucket control valve contains line relief valves for the rod end and the head end of the cylinder. The valve is not pressure compensated.

Except for being pilot controlled, the valve operation is the same as the mechanically controlled bucket control valve.

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SWING CONTROL VALVE HOLD

FROM PREVIOUS VALVE RESOLVERS

SIGNAL METERING SLOT

SWING LEFT

SWING RIGHT

CHECK VALVE

LINE RELIEF VALVE

TO NEXT VALVE

CONTROL SPOOL

PILOT PASSAGE

ADVANCE SIGNAL PASSAGE FLOW CONTROL VALVE

FROM PUMP

94 • Swing control valve in HOLD: - Pilot operated

Except for being pilot controlled, the valve operation is the same as the mechanically controlled swing control valve.

NOTE: A signal limiter was shown in the first verion of this Service Training Meeting Guide and other service literature. The limiter was removed just prior to first ship and is no longer used on the swing circuit for any "D" Series machine.

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BOOM CONTROL VALVE FROM PREVIOUS VALVE

HOLD

ROD END

RESOLVERS

HEAD END

LINE RELIEF AND MAKEUP VALVE

TO NEXT VALVE

CONTROL SPOOL

PILOT PASSAGE

LOAD CHECK VALVE

FROM PUMP

95 • Boom control valve in HOLD: - Pilot operated

Except for being pilot controlled, the valve operation is the same as the mechanically controlled boom control valve.

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2

1

3

96

• Sideshift machines:

Sideshift machines feature a boom (1) that can be shifted to different positions along a frame (2).

1. Boom

Lock pistons (not shown) are used to lock the boom to the frame rails.

2. Frame 3. Stabilizers

The stabilizers (3) are used to raise and lower the machine. Sideshift and center pivot machines use the same type of control valves to operate the stabilizers.

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SIDESHIFT SLIDE LOCK SOLENOID VALVE RELEASED

ENGAGED

SOLENOID

PUMP SUPPLY

PUMP SUPPLY

CHECK VALVE SLIDE LOCK PISTON

SLIDE RAIL SLIDE BAR

97 • Sideshift slide lock solenoid operation for ENGAGED and RELEASED

This schematic shows the sideshift slide lock solenoid and orifice check valve operation.

In the ENGAGED position, the solenoid is not energized. The solenoid blocks the system oil flow. Pump supply pressure can flow past the check valve to the slide lock pistons. The pistons clamp the stabilizer frame slide rails against the bolts on the slide bars to prevent slide frame movement.

The check valve will seat as shown to maintain pressure on the pistons when system pressure decreases.

In the RELEASED position, the solenoid is energized. The solenoid allows system supply oil to go to the tank. The slide lock pistons are no longer pressurized. The slide bar can then move along the slide rail.

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1 2

3

98

• Stabilizer circuit components: 1. Stabilizer valve group 2. Pilot accumulator 3. Pilot pressure test port

The stabilizer valve group (1) and pilot accumulator (2) are mounted on the inside of the rear frame on the right side of the machine.

The pilot accumulator provides dead engine implement lowering capabilities.

The pilot accumulator is not used on the 416D, 424D, 428D and 438D. The pressure test port (3) is used for checking pilot system pressure.

NOTE: All of the lines are not connected in this view. The line from the pilot accumulator is to be connected to the stabilizer valve group.

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416D / 424D / 428D / 438D BACKHOE STABILIZERS HYDRAULIC CIRCUIT SHIFT RIGHT STABILIZER LEFT PILOT RIGHT PILOT LEVER LEVER LEFT STABILIZER

RIGHT STABILIZER

LOCK CHECK VALVES PILOT LOCK CHECK VALVES

CHECK VALVE

ORIFICES RETURN MANIFOLD

PRESSURE REDUCING VALVE

SIGNAL TO BACKHOE SECTION

RESOLVER

SIGNAL FROM LOADER SECTION

FROM PUMP

99 • Stabilizer operation: - Load check valves - Pilot lock check valves

The stabilizer schematic shown is for machines equipped with mechanical controls for the backhoe and loader valve groups. The left stabilizer is in HOLD and the right stabilizer is being SHIFTED. The stabilizer cylinders are controlled by closed-center valves equipped with lock check valve and pilot lock check valves.

The check valves prevent cylinder drift in either direction.

Pilot control valves are used to shift the stabilizer control spools.

Orifices and resolvers are used to signal the pump as to flow needs of the stabilizer circuits.

When a pilot control lever is shifted, pilot oil is sent to one side of the stabilizer control spool to shift it. As the spool shifts, some pilot oil is directed to a pilot lock check valve.

➥

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When the pilot lock check valve shifts, blocked oil that was working with the lock check valve spring to keep the lock check valve seated to prevent cylinder drift is allowed to drain to the tank.

When this occurs, the lock check valve shifts opening one side of the stabilizer cylinder to the tank.

Pump supply oil from the stabilizer control spool now flows through the other lock check valve into one of the stabilizer cylinder ports to move the cylinder either up or down.

Also when the stabilizer control spool is shifted, some of the pump supply oil also becomes signal oil to signal the pump.

When the pilot control lever is released, the spring in the pilot lock check moves to block oil from flowing to the tank through the check valve.

This blocked oil works with the spring on the lock check valve to seat the lock check valves. Oil is now trapped in both sides of the stabilizer cylinders. The stabilizer stay locked in position.

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420D / 430D / 432D / 442D BACKHOE STABILIZERS HYDRAULIC CIRCUIT SHIFT RIGHT STABILIZER LEFT PILOT RIGHT PILOT LEVER LEVER PILOT ACCUMULATOR

LEFT STABILIZER

RIGHT STABILIZER

LOCK CHECK VALVES

CHECK VALVE

PILOT LOCK CHECK VALVES

RETURN MANIFOLD

TO JOYSTICKS

ORIFICES

PRESSURE REDUCING VALVE

PILOT SHUT OFF RESOLVER

SIGNAL TO BACKHOE SECTION

SIGNAL FROM LOADER SECTION

FROM PUMP

100 • Stabilizer circuit for pilot controls:

The stabilizer valves used on machines with pilot controls for the backhoe and loader operate the same as on machines with mechanical controls.

- Pilot accumulator

Machines equipped with pilot controls are also equipped with a pilot accumulator to allow implement lowering capabilities with a dead engine.

- Pilot shutoff solenoid

The key start switch must be turned to the ON position to shift the pilot shutoff solenoid to allow pilot flow to the joysticks.

Refer to the Operation and Maintenance Manual for the respective machine for additional information on lowering the implements if the accumulator has bled down.

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AUTO-UP STABILIZER SYSTEM TIMER ACTIVATED / SOLENOIDS ENERGIZED

1 2

PU-18 BK-18

PU-18 BK-18

LEFT STAB. UP SW.

1 2 CONN. 48

1 2 RIGHT STAB. UP SW.

PU-18 BK-18

PU-18 BK-18

1 2 CONN. 48

ALARM VALVE GP BK-18 1 2 3 4

YL-18 BU-18

1 2

CONN. 17

PU-18 BK-18

1 2 L. STAB UP DETENT

YL-18 BK-18

1 2

YL-18 BK-18

1 2

PU-18 1 2 BK-18 CONN. 48 BU-18 BK-18 PU-18 YL-18

A-1 B-2 B-1 C-1

BAT(+) GND(-) INPUT(S) OUTPUT(L)

STAB. TIMER

R. STAB. UP DETENT DETENT VALVE GP

OR-18 PU-18

+ -

PU-18 BK-18

CONN. 48

1 2 RIGHT STAB. UP SW.

1 2

ALARM DIODE BLOCK

PU-18 BK-18

LEFT STAB. UP SW,

HORN ALARM

1 2 3 4

BK-18

CONN. 12

STAB. LEG ALARM

BK-18 YL-18 OR-18

1 2 3 4 CONN. 12

STAB. LEG UP DETENT

101 • Auto-up stabilizer system

The auto-up stabilizer system is an option that allows the operator to move the stabilizer pilot control lever into a solenoid detent position to raise the stabilizer.

The stabilizer up switches are located in the stabilizer control valve group and are closed by the stabilizer pilot control lever.

The timer holds the control lever in the detent position for approximately 10 seconds. After 10 seconds the stabilizers should be fully raised.

The stabilizer alarm advises operator that the stabilizers are down when the operator shifts the transmission out of NEUTRAL. NOTE: The timer is activated the instant the stabilizer pilot control lever is moved. The timer starts before the lever is placed in the detent position.

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TST 1

TST 2

ALL WHEEL STEER SYSTEM

THERMAL RELIEF VALVE

IRM LEFT VALVE

HOLD

ALL WHEEL STEER CONTROL VALVE GROUP

CIRCLE STEER VALVE

IRM SHUTOFF VALVE

RESOLVER

IRM RIGHT VALVE

PILOT POPPET VALVES LOCK VALVE

RESOLVER

PILOT POPPET VALVES

REAR AXLE

FROM STABILIZER VALVE GROUP

CROSSOVER LINE RELIEF VALVES

TO BACKHOE VALVE GROUP RETURN

AUXILIARY LOADER VALVE GROUP

FRONT AXLE

STEERING METERING UNIT

BACK FLOW CHECK VALVE

TILT LIFT SIGNAL

TO STABILIZER VALVE GROUP STEERING PRIORITY VALVE TO BACKHOE VALVE GROUP

TO BRAKE VALVE

102 All Wheel Steer System (AWS) • All Wheel Steer

The All Wheel Steer (AWS) system is similar to what was used on the "C" Series machines.

Operation of the AWS valve is the same. The major differences between the models are: - Since the "D" Series AWS system uses non-boosted brakes, a steering and brake resolver is no longer in the signal line between the steering priority valve and the SMU. - Due to the reverse signal network, the lines routing between the valve sections has changed.

- The switch to control AWS has been changed to two separate buttons as shown earlier.

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MACHINE SECURITY SYSTEM MACHINE OPERABLE

BATTERY GROUND DRIVER NO. 2 OUTPUT EXCITER COIL SIGNAL LINE DRIVER NO. 1 INPUT DRIVER NO. 1 OUTPUT UNUSED DRIVER NO. 2 INPUT LED GROUND KEY SWITCH ON POSITION INPUT ALTERNATOR R TERMINAL INPUT UNUSED KEY SWITCH CRANK POSITION INPUT UNUSED CAT DATA LINK + CAT DATA LINK UNUSED UNUSED EXCITER COIL RETURN LINE DRIVER NO. 1 GROUND RETURN RED LED SIGNAL LINE GREEN LED SIGNAL LINE DRIVER 2 ENABLE INPUT UNUSED UNUSED UNUSED

1 3 5 7 9 11 13 18 19 24 26 29 31 40 42 45 47 52 53 58 60 62 64 66 68 70

1 2

GN-18 PK-18

MACHINE SECURITY CONTROL (MSC)

EXCITER COIL

A B C

RD-18 BK-18 BU-18 YL-18 PK-18 GN-18

RD-18 YL-18 OR-18

A B C

BU-18 BK-18 PK-18

1 2 3 4

RD-18 OR-18 BK-18 PK-18 YL-18

BK-18 BK-18 GN-18 OR-18

OR-18

PK-18

OR-18 BR-18

YL-18 BU-18 GN-18 PU-18 GN-18 PK-18 YL-18 PK-18

PK-18 PK-18 PU-18 GN-18 GN-18

1 2 3 4 GN-18 PK-18

MSS ENGINE RELAY PK-14

OR-18 BR-18

GN-18 BK-18 PK-18 PK-14

1 2

85 87

86 30

87A

CAT DATA LINK

PU-18 PU-18 GN-18 BK-18

A B C

RED GN-18 BK-18

GREEN

MSS LED INDICATOR

103 OPTIONAL MACHINE SECURITY SYSTEM (MSS) • Machine Security System: - Theft deterrent - Uses Caterpillar Electronic Keys

The Machine Security System (MSS) is a theft deterrent and reduces the chance of unwanted machine operation. MSS uses Caterpillar Electronic Keys that have unique identification numbers. The MSS uses a Machine Security Control (MSC) with the keys. The MSC can be programmed with the key ID's to restrict or allow access to the machine. No two keys have the same ID and are not configurable. Electronic Technician is used to program the MSC.

- Machine Security Control (MSC)

➥

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The exciter coil will read the ID of the key. The exciter coil is mounted around the existing key start switch. The MSC will check the ID of the key for the authorization. If the key is authorized by the MSC, the machine will operate normally. The MSS will keep critical machine functions disabled if the key does not match any authorized keys in the MSC. The MSS LED indicator provides basic MSS information to the machine operator. The green LED indicates the machine is operable, while the red LED indicates the machine is inoperable.

The MSS can be installed in one of two ways: - Disabling power to two items that are currently on the machine.

Solenoids and relays can be controlled with this method.

- Causing another ECM to disable a critical machine function unless an authorized ID key is used.

To make modifications to the MSS, the technician must have a key with Master Access Level for that MSS or a "factory password."

The factory password is determined from the following items: Product ID, Software Part Number from the Machine Security Control, Serial Number from a registered version of ET and a tattletale. A factory password can be used one time.

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104

CONCLUSION • Conclusion

This presentation has provided an overall review of the steering and implement hydraulic systems used in the "D" Series Backhoe Loaders.

When used in conjunction with the service manual, the information in this package should permit the serviceman to do a thorough job of analyzing a problem in these systems.

For service repairs, adjustments and maintenance, always refer to the Owner and Operator Manual, Service Manuals and other related service publications.