MOVING THE VEHICLE — GENERAL INFORMA TION

Braking

A void sudden Constant sudden stops may negatively fect braking performance and driving When leave the clutch (if equipped) engaged long possible use the braking fect the

Caution

When using the braking effect the engine, final gear selection gear selection too high, the vehicle will buck which could cause loss contr ol.

Shifting

Operate a gear low enough allow the engine accelerate (or maintain) governed engine speed when applying full Allowing the engine lug causes excessive strain the which could damage cylinder However , sure not overspeed the

Danger

Always select the proper gear ratio BEFORE descending a grade (to avoid a runaway vehicle and stay within safe and legal speed limits). NOT coast down hills. Gear ratios should selected allow the engine operate between peak torque and rated speed.

Caution

not permit a load drive the engine above governed speed. When descending steep grades, use lower gears and watch the tachometer . Overspeeding will cause sever e drivetrain damage and eventually destr the engine.

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Running the engine a speed that too low for the load (or grade the r oad) can cause damage the

Shifting the proper time will result increased fuel ficiency , well a decrease costly repairs. Remember that once the engine falls below peak torque, both torque and horsepower will drop f very rapidly . Before this happens, downshift the next lower gear .

For vehicles with transmissions that have extreme reduction gearing coupled with high rear - axle a torque - limiting device should This device limits the amount fuel that can delivered the engine and prevents overloading drivetrain components while extreme reduction

Always use the same gear going downhill uphill. This will reduce brake wear and prevent damage the engine from overspeeding.

Engine T emperature

Before entering high - speed traf fic allow the engine reach normal operating A normal operating range between 77°C and 104°C (170°F and 220°F) for stationary

Clutch (If Equipped)

T o avoid shock damage, release the clutch pedal smoothly , without shock - loading the driveline (especially grades while carrying heavy loads). not ride the clutch pedal. Premature wear the clutch facing and release bearing may result.

Caution

Always use the lowest drive gear combination start the vehicle moving avoid ematur e clutch failur

T o move the vehicle, start the engine and wait until reaches operating temperature.

Disengage the clutch pushing the pedal the floor .

Shift the transmission into first gear (see ransmission Shifting for specific https://www.truck-manuals.net/mack/

Release the parking brake.

Caution

the Parking Brake indicator NOT attempt move the vehicle because driveline damage may r

Engage the clutch smoothly allowing the clutch pedal come slowly . For comfortable starts, not apply the accelerator until the clutch begins engage.

Caution

Never allow your foot ride the clutch pedal when the clutch This will cause ematur e failur e and incr eased clutch wear the vehicle gains continue shifting until the transmission the highest gear possible (with engine operating

Note: When the vehicle equipped with a torque - limiting the engine must warmed operating temperature before attempting move either REVERSE

Clutch Brake Operation

The clutch brake designed stop the rotation the transmissions input shaft while the truck standing still. This makes shifting into first reverse gears easier Inadvertent use the clutch brake will make shifting from a gear dif ficult shifting from reverse with the clutch brake applied and the vehicle https://www.truck-manuals.net/mack/

Normal Clutch Pedal T ravel Depress Pedal Last One Inch Engage Clutch Brake

With the vehicle standing apply the clutch brake pushing the clutch pedal all the way the floor; the clutch brake applied when the clutch pedal f u l l y d e p r e s s e d (the last one inch travel past normal pedal

Note: When the clutch a slight but definite resistance clutch pedal downward travel will felt the last one inch.

Shift the transmission into first reverse gear , engage the clutch and accelerate. The clutch brake only used when the vehicle stopped and shifted into first reverse gears. not designed used upshifting aid.

Caution

Clutch brake damage may r esult used while the vehicle The clutch brake must NOT used when making a downshift

Double - Clutching

Double - clutching a way bring the speed the transmission gears into synchronization that the shift can made without a clash. The engine https://www.truck-manuals.net/mack/ used speed the countershaft for a downshift and slow down for upshift.

Note: For all nonsynchronized transmissions, double - clutching necessary downshifts and advisable use the torque - limiting clutch brake engage first and REVERSE gears and double - clutch for gear ratio changes.

Depress the clutch pedal and shift

Release the clutch pedal and increase (downshift) decrease (upshift) engine speed until roughly corresponds the road speed the desired gear

Depress the clutch pedal and complete the shift. Then release the clutch pedal.

POWER T AKE-OFF (PT OPERA TION

the vehicle equipped with a Power T ake - f (PT unit, sure read the following section.

Precautions

Danger

Power T ake - f (PT units and related equipment can very dangerous. Any O installation, repair replacement should include a warning indicator light which indicates O engagement. The light must located close the O control and clearly visible the operator .

Danger

O units are driven engine drivetrain components (flywheel, crankshaft, transmission). not attempt service the O and related units unless the engine shut down.

Danger

Always keep body parts and loose - fitting clothing out the range drivetrain components, personal injury may result.

Danger

Always aware the current O status (engaged disengaged) and the position the vehicle body (dump body controlled etc.). sure disengage the O when not use.

Danger

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Classification

Rear - mounted O units, for MACK transmissions, are categorized according operation.

Intermittent Service The O unit under for less than seven minutes and then allowed cool before operated

Note: a O unit operated for less than seven minutes but allowed cool down before operating again, considered Continuous Service.

Continuous Service — The O unit operated, under load, for seven minutes more.

Note: Rear - mounted O units operating under the Continuous Service guideline must not run more than 70% the O output - rated torque/horsepower

Side-Mounted

Locations

The first choice location for Side - Mounted either the O openings the main box.

The second which the compound O restricted those applications specifically requiring multi - speed with reverse capability , such some mechanical winches unique speed multiple O However , a word caution order when using these Operators should trained understand and follow the proper operating procedures described the cab and avoid using the neutralizing feature a power disconnect for vehicle

Operating Procedures

Specific O operating procedures are described the end applicable transmissions the following section.

Transmission Shifting Instructions

Caution

The maximum safe operating oil temperatur e for MACK transmissions 121°C (250°F) for mineral - based oil, and 148°C (300°F) for synthetic - based oil. Continued operation with oil above this temperatur e will r esult rapid deterioration the s lubricating operties and NOT r ecommended.

Caution

T o avoid transmission damage, the vehicle must completely stopped befor e being shifted REVERSE any forwar d speed (and vice versa).

Caution

Never coast with the transmission

Never coast with the clutch depr

Shifting Instructions for Allison Automatic T ransmissions

Please refer the applicable Allison automatic transmission operators manual provided with your vehicle for complete shifting and operating instructions.

MACK T306G Shifting Instructions

The T306G a six - speed overgear , non - synchronized transmission designed for general highway Shifting accomplished through a single shift lever using the traditional H

Upshift — Start out first gear and shift second, third, fourth, fifth and sixth gears, double - clutching from one gear the next.

Downshift

Downshift reverse order (sixth through double - clutching through each gear

MACK TM308 Shifting Instructions

Caution

Make sur e air essur e least psi and unit warmed befor e shifting the transmission. T o avoid transmission damage, NOT change range while moving REVERSE. Use the clutch brake for shifting into first and r everse gears only . not use the clutch brake shift out gear . car eful not overspeed the engine during downshifting. Damage powertrain components can r esult.

The TM308 a non - synchronized transmission having a total eight speeds (6+2) with a non - synchronized air shifted compound section. This and auxiliary compound section controlled air - shift range selector valve located the shift lever . The range has two low gear ratios. range there are six forward gears which can shifted the normal manner , but remember double - clutch whether moving down through the gears.

F o r n o r m a l h i g h w a y u s e , s t a r t i n H I r a n g e , r s t g e a r and shift through second, third, fourth, fifth and sixth. The ratio step between fifth and sixth smaller than all the other ratio steps. The two gears range are designed for f - highway use and slow - moving operations (curb pouring, material spreading, heavy load, steep grade).

Reverse Reverse can used range. T o m a k e a r a n g e s h i f t i n r e v e r s e , bring the truck a complete stop. Flip the range selector lever range desired.

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