several transmission upshifts and downshifts; during this learning
process, slightly firmer shifts may occur. After this learning process,
normal shift feel and shift scheduling will resume.
P (Park)
This position locks the transmission and prevents the rear wheels from
turning.
To put your vehicle in gear:
1. Start the engine
2. Press the brake pedal
3. Move the gearshift lever into the desired gear
To put your vehicle in P (Park):
1. Come to a complete stop
2. Move the gearshift lever and securely latch it in P (Park)
WARNING:Always set the parking brake fully and make sure
the gearshift is latched in P (Park). Turn the ignition to the off
position and remove the key whenever you leave your vehicle.
R (Reverse)
With the gearshift lever in R (Reverse), the vehicle will move backward.
Always come to a complete stop before shifting into and out of R
(Reverse).
N (Neutral)
With the gearshift lever in N (Neutral), the vehicle can be started and is
free to roll. Hold the brake pedal down while in this position.
D (Drive)
This is the normal driving position for the best fuel economy. This
position allows automatic upshifts and downshifts through gears one
through six.
4 (Fourth)
This position allows automatic upshifts and downshifts in gears one
through four.
2 (Second)
Use 2 (Second) to start-up on slippery roads or to provide additional
engine braking on downgrades.
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1 (First)
•Provides maximum engine braking.
•Allows upshifts by moving gearshift lever.
•The transmission will not downshift into 1 (First) at high speeds; it
will downshift to a lower gear and then shift into 1 (First) when the
vehicle reaches slower speeds.
Forced downshifts
•Allowed in 4 (Fourth).
•Press the accelerator to the floor.
•Allows transmission to select an appropriate gear.
Allison 2200 with parking pawl feature
Note:For Allison automatic transmission-equipped vehicles, also refer to
the separateAllison 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 when parking the vehicle.
WARNING:Always set the parking brake fully. Do not use the
gearshift in place of the parking brake.
Note:If the P (Park) position is selected when the vehicle is in motion,
the parking pawl mechanism ratchets andDOES NOThold the truck.
WARNING: 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.
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Allison 2500
This transmission is available with a column-mounted gearshift lever. The
gear positions are displayed on the RNDL in the instrument cluster.
WARNING: 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.
Transmission fluid operating temperatures - 2200/2500 models
Allison 2200 and 2500 models:The sump/fluid reservoir temperatures
should not exceed 250°F (120°C). The converter temperature should not
exceed 300°F (144°C). he sump/fluid reservoir temperature should not
exceed 250 F (120 C).
TorqShift6-Speed models:The sump/fluid reservoir temperatures
should not exceed 250°F (120°C).
Allison 3000 series
The Allison 3000 Series offers two shift modes: Performance and
Economy. Performance Mode gives the best all-around transmission
operation; Economy Mode provides operation at lower engine RPM while
maintaining adequate performance. The transmission defaults to
Performance Mode when you start the engine. Pressing MODE on the
shifter activates Economy Mode and illuminates the Mode ON lamp.
If the engine speed is above idle when a gear is selected using the
shifter, the vehicle won’t move; the shifter must be moved to re-select a
gear after the engine speed returns to idle.
Note:For more information regarding the Allison 3000 Series, refer to
the separateAllison 3000 Series 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 parking pawl, making it 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.
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WARNING:Do not coast the vehicle with the clutch pedal
pressed or with the transmission in neutral. This practice could
result in loss of vehicle control.
To go forward
With the engine idling, press the clutch pedal in and shift into 1 (First).
Engage the clutch while pressing the accelerator to start forward.
Operate the clutch and upshift as required by driving conditions.
To go backward
Put the gearshift lever in R (Reverse) and engaging the clutch while
pressing lightly on the accelerator.
Shifting with a synchronized transmission
With the clutch pedal pressed in, use the 2 (Second) gear synchronizer
to stop the clutch disc rotation; this allows smooth engagement of 1
(First) or R (Reverse). To complete the gear engagement, it may be
necessary to apply light pressure to the gearshift lever during initial
engagement of the clutch. It takes a second or two to match gear speeds;
steady pressure on the gearshift lever helps the synchronizer perform its
job more quickly. If the gearshift lever is forced into position, this action
defeats the purpose of the synchronizer by causing gear clash.
Shifting with a non-synchronized transmission
Refer toClutch brakeandDouble clutch proceduresin theClutch
section of this chapter.
Operating the Eaton FS-5205A 5–speed transmission
This transmission is equipped with
five forward gears and one reverse;
gears 2–5 are synchronized. The
shift pattern is embossed on the
gear shift knob.
Do not shift the transmission into R (Reverse) while the vehicle is
moving as this could damage the transmission.
R 2 4
3 5 1
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PTO operation with vehicle stationary
Stop the vehicle, idle the engine and set the parking brake. Make sure the
gear selector is in any forward drive range, then engage the PTO. After the
PTO is engaged, move the range selector to N (Neutral). Increase the engine
speed until the desired PTO operation speed is obtained. To disengage the
PTO after operation with the vehicle standing, release the throttle, allow the
drive equipment to come to a stop, and then disengage the PTO.
WARNING:When the PTO is operated with the vehicle
stationary, the transmission must be placed in N (Neutral) with
the parking brake set. If the transmission is not in N (Neutral) and is
equipped with a remote throttle control, an increase in engine speed
can overpower the parking brake and cause the vehicle to move,
possibly resulting in personal injury and/or property damage.
PTO operation while vehicle is moving
After the PTO is engaged for driven vehicle operation, shift to the desired
range and drive the vehicle. The speed of the PTO, during this period of
operation, always maintains direct relation to vehicle speed. PTO speed
decreases in relation to vehicle (transmission output) speed as shifts to a
higher gear occur. When operating the PTO while the vehicle is moving,
the PTO may be disengaged whenever it is no longer required. When there
is no load on the PTO gear, it can be pulled out of engagement.
Vehicles equipped with an Allison 3000 Series automatic transmission
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.
Vehicles equipped with a manual transmission
Transmission-mounted PTO units are available for local installation on
your vehicle. See yourBody Builder’s Layout Bookfor restrictions on
use and installation of PTO units.
To engage the PTO unit, stop the vehicle and place the transmission in N
(Neutral). Press the clutch and allow the gears to stop rotating, then
engage the PTO unit. The PTO can also be selected with the
transmission in gear as long as the clutch is pressed.
When operating the PTO with the vehicle stationary, first set the parking
brake (chock the wheels if the vehicle is on a hill or another uneven
surface).
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REAR AXLE INFORMATION
Axle operating temperature normally don’t exceed 100°F (38°C). If the
operating temperature exceeds 230°F (110°C), the rate of axle
lubrication oxidation increases and shorten the life of the lubricant and
seals, requiring axle lubrication changes to become more frequent to
preserve the axle. Extreme Pressure (EP) lubricants should not be run
consistently above 230°F (110°C).
Gross axle weight
Your truck has gross axle weight, gross vehicle weight and gross
combination weight ratings. Do not exceed these ratings.
WARNING:Exceeding these ratings by overloading can cause
component failure resulting in property damage, personal injury
or death.
Rear axles with locking or limited-slip differentials (if equipped)
If your vehicle is equipped with a locking or limited-slip differential, note
the following:
•Power is transmitted to the opposite wheel should one of the wheels
begin to slip.
•Both wheels must be raised off the ground should it be necessary to
operate one wheel with the vehicle stationary.
WARNING:If both wheels are not raised off the ground, the
one wheel that is not raised may pull the vehicle off its support,
possibly resulting in personal injury
Driver-controlled differential lock
To prevent the vehicle from moving when servicing the wheels, tires or
brakes, turn the engine off and raise all drive wheels of the locker
differential axle. Axles equipped with NoSPIN Detroit Locker differentials
deliver power to both wheels even when only one wheel is on the
ground.
WARNING:Failure to raise all drive wheels with this type of
differential could cause the vehicle to move unexpectedly,
resulting in property damage, personal injury or death.
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Care should be taken to avoid sudden accelerations when both drive
wheels are on a slippery surface.
WARNING:Sudden accelerations on slippery surfaces could
cause the wheels to spin, the vehicle to turn sideways on a
crowned road surface or in a turn, possibly resulting in loss of vehicle
control and personal injury.
Some drive axles have a driver-controlled differential lock. The
differential lock can lock or unlock the differential when the vehicle is
moving or stopped. When extra traction is required, the differential lock
provides full power to both axles.
When the differential is locked, the vehicle’s turning radius increases
(vehicle “under-steers”).
The differential can be locked or unlocked when the vehicle is moving at
a constant speed of under 25 mph (40 km/h) and while the wheels are
not slipping. The differential must not be locked when the vehicle is
traveling down steep grades and traction is minimal.
Note:Never use the differential lock at vehicle speeds above 25 mph
(40 km/h).
The differential lock and differential lock light automatically disengage at
speeds above 25 mph (40 km/h). The differential lock remains off until
either the vehicle is restarted or the differential lock switch is turned off
then back on.
Axle conversions
It is not recommended, or approved, for axle conversions to be
performed. However, it is understood that, on occasion, aftermarket
add-on axles are installed by others on the truck chassis which allow
operator control for weight transfer from other axles (i.e., air lift axles).
WARNING:When operating a loaded vehicle, the driver must
keep all adjustable axles on the ground at all times, supporting
their share of the vehicle’s load. Failure to do so can overload other
axles, tires, wheels, springs, steering components, brakes and frames,
resulting in early component failure, loss of vehicle control, possible
property damage and personal injury.
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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.
WARNING: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 press 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 LOW when you drive a fully-loaded vehicle on a severe grade or
in congested traffic. To activate LOW, press the upper portion of the
switch.
•Use HIGH for all normal driving conditions with a lightly-loaded or
partially-loaded vehicle. To activate HIGH, press the lower portion of
the switch.
Note:You can’t split-shift with an automatic transmission. Also,
downshifting above 40 mph (64 km/h) may result in transmission or axle
damage.
To shift the axle from LOW to HIGH with the vehicle stopped, place the
transmission in N (Neutral), then press the lower part of the switch.
2SPD
LOW
HIGH
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