Volvo Fh Truck Vto2514b Gearbox Construction Manual

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Chassis ID

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Path

4/Description, Design and function/FH, VTO2514B/Gearbox construction Model

Identity

FH

107716616

Publish date

Operation no.

08 June 2006 Gearbox construction

Contents Gear selector housing Pneumatic system Electrical system Lubricating system Gear selector housing

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The control housing is made of aluminium.

The control shaft and control housing have been adjusted for the optional construction of left-hand and right-hand driven vehicles. z z z z z

Inhibitor cylinder (A) Solenoid for the first gear inhibitor (B) Neutral/reverse inhibitor with adjusting spacer (C) Inhibitor valve (D) Reverse light contact with pin (E)

The function of the control housing is to transfer the gear shift movement to the selector bars in the gearbox and consists primarily of: z z z z z

The control shaft (G) on which the gear shift is attached.

The gear selector (H) on the gear shift affects the selector bars.

The gear position detent (I) prevents two selector bars from being affected at the same time.

The control shaft is also equipped with a neutral/reverse inhibitor (C) that keeps the gears in place.

In addition, the lock functions as a gear lever resistor when put into reverse/crawl.

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The neutral/reverse inhibitor locks against the cam (F) on the control shaft. The cam also has a catch that is locked by the first gear inhibitor's solenoid.

Pneumatic system Positioning of pneumatic components

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Gear lever Air filter Range cylinder Relay valve range Inhibitor valve for range housing Interlock cylinder Inhibitor valve for control housing Range inhibitor Split cylinder Split relay valve Split inhibitor valve

Gear lever

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The range gear control is positioned on the gear lever. This consists of a valve that stops or lets through control air to the relay valve on the range cylinder.

The split gear control that stops or lets through control air to the split cylinder relay valve is also positioned on the gear lever.

The gear lever is fed with pressurised air through the connection (1). When the range control is set on low range, control air is let out through the connection (21). When it is set on high range, a connection is made via the gear lever.

When the split control is set on high split, control air is let out through the connection (22). When it is set on low split, a ventilation is performed through the gear lever.

Air filter

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The pneumatic system's gearbox feeder is fitted with an air filter. This is positioned on the cover of the inhibitor cylinder on the control housing.

Range cylinder

The range cylinder is a double-acting pneumatic cylinder attached to the back of the range housing. The piston is screwed onto the piston rod and the coupling is sealed with an O-ring (1). Other seals comprise of a piston seal (2), a piston rod seal (3), the O-ring seal on the range housing (4) and the O-rings on the cover (5).

Relay valve range

The function of the relay valve is to direct the air to one side of the piston depending on the choice of gear. The relay valve is integrated in the cylinder cover.

The relay valve is fitted with a spring-loaded control slide (1) that is set on high range (H) by a spring force (2). When the control on the gear lever is set on low range (L), control air is let through to the relay valve, overcoming the spring force and making the control slide shift a to low range level.

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The cylinder is ventilated through the relay valve.

Inhibitor valve range housing

When changing the range gear, the base gearbox is locked by the inhibitor cylinder in the control housing. The inhibitor valve controls the feed air to the inhibitor cylinder. The inhibitor valve is controlled by the range cylinder piston rod in the following way: The piston rod has two indents. The piston of the inhibitor valve is located in one of these indents when the range gear is set to a high or low range level.

The valve then blocks the air supply to the inhibitor cylinder on the control housing.

When changing the range gear, the inhibitor valve's piston is pushed out of the indent, opening the air supply to the inhibitor cylinder.

Inhibitor cylinder

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The inhibitor cylinder on the control housing stops the base gearbox from being manually changed when the range gear is changed.

The inhibitor cylinder consists of a double-action spring-loaded cylinder and a piston with a stop pin.

When changing the range gear, air from the inhibitor valve on the range gear is emitted into the connection (1) at the same time as the force of the spring pushes the stop pin into the recess on the gear selector. The base gearbox is then locked into neutral position.

The inhibitor cylinder is also used to lock the gear lever in a neutral position when releasing the clutch pedal. This results in the driver always having to depress the clutch pedal before engaging the start gear.

When the clutch pedal is depressed, air from the split inhibitor valve is emitted into the connection (2).

The air overcomes the spring force, putting the gear selector into neutral.

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Inhibitor valve control housing

When any of the gears in the base gearbox is engaged, a change of range gear is not possible. This is carried out by an inhibitor valve that functions in the opposite way to the inhibitor valve on the range housing.

When the gear lever is put in neutral, the inhibitor valve opens for the feed air to pass through to the range cylinder.

When a gear is engaged, the gear selector pushes in the piston on the inhibitor valve, shutting off the air supply to the range cylinder.

Range inhibitor

The range inhibitor prevents a change to low range when the rotation speed on the output shaft of the gearbox exceeds 700 rpm (approx. 30 km/h).

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The vehicle control unit (VECU) receives a signal from the vehicle speed sensor and activates the solenoid valve that in turn shuts off the control air to the range cylinder relay valve, preventing a low range from being engaged.

The solenoid valve is positioned on the cover of the range cylinder.

Split cylinder

The split cylinder is a double-action pneumatic cylinder inside the clutch housing.

The cover and cylinder are made in one piece (A). The piston (B) is screwed onto the piston rod. The inhibitor that holds the split gear in place is situated to the left of the base gearbox, next to the split switch.

Relay valve split

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The split cylinder relay valve acts in the same way as the range cylinder relay valve.

The relay valve slide is kept in a low split position (L) by the spring force.

When the gear lever control is put in a high split position (H), air is emitted from the relay valve, overcoming the spring force and putting the control slide in a high split position.

(Only applies to direct drive gearbox, DD) Inhibitor valve split

The split gear cannot be changed unless the clutch pedal is depressed. The feed air supply to the split cylinder is therefore controlled by an inhibitor valve.

When depressing the clutch pedal, the inhibitor piston is pushed in, opening the valve and letting through feed air to the split cylinder.

Electrical system

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1 is an inhibitor solenoid for the first gear. The inhibitor solenoid prevents the driver from putting the gear lever in first gear when the speed is too high. This function protects the synchronisation and clutch. The following conditions must be fulfilled to activate this function: { 1. Low range position { 2. Speed of over approx. 20 km/h 2 is a split switch that illuminates the split lamp on the dashboard.

3 is a reverse light contact that illuminates the reverse light/buzzer when the reverse gear is engaged.

4 is a range position sensor that provides the vehicle control unit (VECU) with information about the position of the range to activate the first gear's solenoid cylinder in case of an incorrect gear change.

5 is a solenoid valve for the range inhibitor. The solenoid valve prevents a gear shift to a low range when the speed exceeds approx. 30 km/h.

6 is a speed sensor that provides the vehicle control unit (VECU) with a speed signal.

7 is an oil temperature sensor indicating the oil temperature in the gearbox (only accessory).

Lubricating system General

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The gearbox is lubricated through a combination of pressure and splash lubrications.

The gearbox has a built-in circulation system lubrication. The oil is extracted from the bottom of the gearbox through a filter and to the oil pump that is powered by the countershaft.

The oil is forced into the rear cover of the main shaft and then out into the oil distributor pipe where it is forced through a number of holes to the bearings on the input shaft, main shaft and range gear.

Gearboxes with OD have an extra oil pipe from the rear mainshaft cover to the OD gear.

The ducts then direct the oil to the bearings and synchronisation.

Approximately 30% of the oil is distributed to the main shaft and the remaining 70% to the range gear.

Oil pump

The oil pump is an eccentric pump powered by the countershaft via a gear shaft and an axle shaft and through a reverse shaft. The axle shaft is placed on bearings with two needle bearings in the reverse

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shaft.

The pump is fitted with two overflow valves. One of the valves (1) makes sure that the gearbox is lubricated in case of a filter blockage and the other valve (2) protects against a high system pressure (e.g.cold start).

The valves positioned in the pump housing consist of a compression spring and valve peg.

The oil flow has been increased by 20% compared with SR1900.

The pump compression face is fitted with a full flow insert filter (3). This is positioned on the pump housing and is accessible from outside. The filter is protected with a cover (4) on the range housing. The oil filter incorporates a stay tube (5) that prevents the filter from collapsing.

Oil cooler

The gearboxes can be fitted with an oil cooler.

An additional oil filter cover (2) onto which the oil cooler is screwed can also be used.

The oils is first pumped through the filter, then through the oil cooler and finally through the pipe to the gearbox oil ducts (1).

Coolant from the engine's cooling system is directed through pipes and hoses to the oil cooler's heat exchanger.

When necessary, a high power oil cooler can be used as an alternative. The oil cooler (3) must then be exchanged for an adapter leading the oil to a larger cooler.

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Š Copyright Volvo Parts Corporation The information contained herein is current at the time of its original distribution, but is subject to change. The reader is advised that printed copies are uncontrolled.

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