Unexpected and possible sudden vehicle movement may occur if
these precautions are not taken.
If the service brakes should fail to operate while the vehicle is in motion,
you can make an emergency stop with the parking brake. The stopping
distance, however, will be much greater than normal. Repairs should be
made immediately to an inoperative air brake system circuit.
Parking brake control (knob)
Pull the yellow parking brake knob
out to apply the parking brake. Push
the knob in to release the parking
brake.
This control is used for
parking only. Do not leave
the vehicle unattended after
setting the parking brake without
placing the transmission in R
(Reverse) for manual
transmission, N (Neutral) for
automatic transmission (except
Allison 2400 transmission) or P
(Park) (Allison 2400
transmission). Use of wheel
chocks is also recommended in
hilly or off-road usage.
The parking BRAKE warning lamp
in the instrument cluster illuminates
and remains illuminated (when the
ignition is turned ON) until the
parking brake is released.PARKING
BRAKE
PULL TO
RELEASE
APPLY
PUSH TO
P
BRAKE
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9. Charge the trailer brake system. Set the trailer brakes, either with the
hand valve or tractor protection valve. Pull against the trailer for an
additional check of proper hook-up. Do not pull hard enough to damage
or strain the equipment.
10. Set the tractor parking brakes and fully raise the trailer landing gear.
Refer toBrakesin this chapter for proper operation of the parking brake
and trailer brakes.
11. Check the operation of all trailer lights and correct any lights that
may be faulty.
Un-hook
1. Try to keep the tractor and trailer in a straight line.
2. Apply the parking brakes.
3. Lower the trailer landing gear, making sure it is on solid, level ground.
The weight of the trailer is to be on the landing gear.
4. Block the trailer wheels.
5. Disconnect the brake hoses and light cords. Be sure hoses and cords
are clear.
6. Pull coupler release lever to disengage the fifth wheel jaws.
7. Release the tractor parking brakes.
8. Pull out from the trailer slowly, allowing the landing gear to take the
load gradually.
AUTOMATIC TRANSMISSION OPERATION (IF EQUIPPED)
Main transmission, auxiliary transmission, transfer case and power
take-off (PTO) control shift patterns can be found on a placard or decal
on the driver’s sun visor, on the instrument panel or on the shift control
itself.
The main transmission control is used to select the various gear ratios or
speeds of the transmission. Selecting D (Direct Drive), does not change
the transmission gear ratio, but is used where the gear ratios in the main
transmission are adequate to handle the vehicle operation.
Hold the brake pedal down while you move the gearshift lever
between positions. If you don’t hold the brake pedal down, your
vehicle may move unexpectedly and cause property damage, personal
injury or death.
Allison 2000 automatic transmission
This transmission is available with a column-mounted gearshift lever. The
gear positions are displayed on the RNDL in the instrument cluster.
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To avoid sudden, unexpected vehicle movement and possible
personal injury or death:
1. Bring the vehicle to a complete stop.
2. Shift the transmission into: N (Neutral).
3. Apply the parking brake and make sure it is holding properly.
4. Turn the engine off when you leave the vehicle.Never leave the
vehicle unattended when the engine is running.
Allison 2400 automatic transmission with park pawl feature
Note:For Allison automatic transmission-equipped vehicles, also refer to
the separate Allison Transmission Operator’s Manual.
A parking pawl effectively grounds the transmission’s output shaft
preventing rotation of the driveline. If the vehicle is stationary, selecting
the P (Park) position places the transmission in neutral and engages the
parking pawl (always use the parking brake, also).
Note:If the P (Park) position is selected when the vehicle is in motion,
the parking pawl mechanism will ratchet andNOThold the truck.
Always set the parking brake fully. Do not use the gearshift in
place of the parking brake.
To avoid sudden, unexpected vehicle movement and possible
personal injury or death:
1. Bring the vehicle to a complete stop.
2. Shift the transmission into: P (Park). Slowly lift your foot from the
brake pedal to engage the transmission parking pawl mechanism.
3. Apply the parking brake and make sure it is holding properly. Do not
rely solely on the parking mechanism of the transmission.)
4. Turn the engine off when you leave the vehicle.Never leave the
vehicle unattended when the engine is running.
Allison MD (Medium Duty) electronic World Transmission (WT)
Two modes are available for the Allison MD-WT: Performance and
Economy. Performance mode will give you the best all-around
transmission operation; Economy provides operation at lower engine
RPM while maintaining adequate performance. The transmission will
automatically default to Performance mode when you start the engine.
Pressing MODE on the shifter will activate the Economy mode; this will
also illuminate the Mode ON lamp.
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If the engine speed is above idle when a gear is selected using the
shifter, the vehicle will not move. To move the vehicle, the shifter must
be moved to re-select a gear after the engine speed returns to idle.
Note:For more information regarding the Allison MD-WT, refer to the
separate Allison MD-WT Operator’s Manual.
Torque lock
If your vehicle is parked on an incline and P (Park) is not properly
engaged (The parking brake is not applied before the transmission is
shifted into P [Park]), the weight of the vehicle may generate an
excessive amount of torque on the park pawl. In this situation, it may be
difficult to shift the transmission out of P (Park). Hold the brake pedal
down while shifting out of P (Park), then release the parking brake.
Allison MD (Medium Duty) push-button shifter
To shift the transmission into R
(Reverse) or D (Drive), depress the
brake pedal, then press R or D, then
release the brake pedal. To select a
lower range when in D (Drive),
press the down-arrow button. To
select a higher range when in D
(Drive), press the up-arrow button.
To place the transmission in N
(Neutral), press N.
Automatic transmission operating temperatures
Allison 2000/2400–The sump/fluid reservoir temperatures should not
exceed 120°C (250°F). The converter temperature should not exceed
144°C (300°F).
Power take-off (PTO) operation with an Allison automatic
transmission (except MD applications and vehicles equipped with
a Caterpillar 3126E engine)
The power take-off can be operated while the vehicle is standing or
moving.
To engage the PTO, apply the brakes and shift to any gear other than N
(Neutral) - this stops the rotation of the PTO drive gear in the
transmission - then engage the PTO.
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Power take-off (PTO) operation with an Allison automatic
transmission (MD applications)
The PTO drive gear is engine driven and provides direct engine power.
The PTO can be operated when the vehicle is either stationary or
moving.
The PTO gear is in constant mesh with the drive gear in the torque
converter housing. A friction clutch or constant drive is used to transmit
power to the PTO.
CLUTCH (IF EQUIPPED)
Properly maintain the clutch to prolong it’s life. Do not ride or slip the
clutch as this will cause unnecessary heat and wear.
Clutch precautions
Maintain specified clutch adjustment; regularly inspect the clutch control
linkage for tightness.
When adjustment of the clutch is necessary, it is very important that the
work be performed properly or early clutch failure may result and a
costly clutch overhaul may become necessary. Clutch work should only
be performed by a qualified technician.
Engaging the clutch
•Always start in the proper gear.An empty vehicle can start in a
higher gear than a fully loaded vehicle. Starting in too high a gear can
cause clutch slippage and excessive heat and wear on the clutch. A
gear that will start the vehicle moving at idle speed is the correct gear.
If the engine has to be revved to get the vehicle going, the gear
selection is too high.
•Do not shift until the vehicle has reached the proper speed.
Upshifting before the vehicle has reached the proper speed can cause
clutch slippage and excessive heat and wear on the clutch.
•Never hold a vehicle on a grade with the clutch.This will cause
the clutch to slip and can actually burn up the clutch.
•Never coast with the clutch disengaged.The high RPM
(sometimes over 10,000), can actually burst the facing material of the
clutch.
•Never engage the clutch while coasting.Re-engaging the clutch
after coasting may not only cause a great shock to the clutch, but the
whole drivetrain. Internal engine damage and/or clutch and flywheel
failure can result from this.
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TWO-SPEED REAR AXLE (IF EQUIPPED)
A two-speed rear axle allows the driver to select a LO range for greater
pulling power and a HI range for greater road speed and fuel economy.
These ranges can also be used to provide additional steps between
transmission shifts when driving on steep grades and/or fuel economy
may be factors.
Note:Do not shift between ranges when the speed control is on.
Never shift a two-speed axle when descending a steep grade as
this may cause loss of vehicle control and result in personal
injury.
Axle shifting
Manual transmissions:
•To downshift,select the next lower gear, release and depress the
accelerator pedal rapidly, or while holding the accelerator pedal down,
release and engage the clutch rapidly.Note:The clutch method is
recommended when driving at slower speeds.
•To upshift,keep the accelerator pedal down, select the next higher
gear, release the accelerator and pause until the axle upshifts.Note:
De-clutch for smoother axle upshifts when driving at slower speeds.
Automatic transmissions:
•Use LO range for when you drive
a fully loaded vehicle on a severe
grade or in congested traffic. To
activate LO range, press the
upper portion of the switch.
•Use HI range for all normal
driving conditions with a lightly
loaded or partially loaded vehicle.
To activate HI range, press the
lower portion of the switch.
Note:You cannot split-shift with an automatic transmission. Also,
downshifting above 64 km/h (40 mph) may result in transmission or axle
damage.
Shifting the axle from LO to HI range - vehicle stopped
Place the transmission in N (Neutral), the press the lower part of the
switch.
LOW
2SPD
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Trailer brakes
Electric brakes and manual, automatic or surge-type trailer brakes are
safe if installed properly and adjusted to the manufacturer’s
specifications. The trailer brakes must meet local and Federal
regulations.
Do not connect a trailer’s hydraulic brake system directly to your
vehicle’s brake system. Your vehicle may not have enough
braking power and your chances of having a collision greatly increase.
Trailer lamps
Trailer lamps are required on most towed vehicles. Your vehicle may be
equipped with one of two possible trailer wiring designs. Make sure all
running lights, brake lights, turn signals and hazard lights are working.
See your dealer or trailer rental agency for proper instructions and
equipment for hooking up trailer lamps.
Driving while you tow
When towing a trailer:
•Turn off the speed control. The speed control may shut off
automatically when you are towing on long, steep grades.
•Consult your local motor vehicle speed regulations for towing a trailer.
•To eliminate excessive transmission shifting, use a lower gear. This will
also assist in transmission cooling.
•Anticipate stops and brake gradually.
•Do not exceed the GCWR rating or transmission damage may occur.
Servicing after towing
If you tow a trailer for long distances, your vehicle will require more
frequent service intervals. Refer to your scheduled maintenance guide for
more information.
Trailer towing tips
•Practice turning, stopping and backing up before starting on a trip to
get the feel of the vehicle trailer combination. When turning, make
wider turns so the trailer wheels will clear curbs and other obstacles.
•Allow more distance for stopping with a trailer attached.
•The trailer tongue weight should be 10–15% of the loaded trailer
weight.
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•After you have traveled 80 km (50 miles), thoroughly check your
hitch, electrical connections and trailer wheel lug nuts.
•To aid in engine/transmission cooling and A/C efficiency during hot
weather while stopped in traffic, place the gearshift lever in P (Park)
(if available on your automatic transmission) or N (Neutral) (manual
transmissions and automatic transmissions without a P [Park]
position).
•Vehicles with trailers should not be parked on a grade. If you must
park on a grade, place wheel chocks under the trailer’s wheels.
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