The high idle speed will be temporarily interrupted and
the engine speed will return to normal if any of the
following conditions occur:
•The brake pedal is applied.
•The accelerator pedal is pressed.
•The automatic transmission is shifted out of
PARK (P) or NEUTRAL (N).
•The clutch pedal on the manual transmission is
pressed.
•Vehicle speed is detected.
Once these inputs are removed, the engine idle speed
will slowly ramp back up to high idle after the normal
delay, if the conditions for engine coolant temperature
and air intake temperature are still met.
If this feature is turned off, by doing the brake stomp
procedure described above, and then the engine
is started the exhaust brake/restrictor light will flash for
10 seconds and then it will turn off.
Engine Checks Before Operating
When you have started your engine, let it run for
20 to 30 seconds before you put a load on the engine.
But do not leave the vehicle while the engine is running.
Avoid unnecessary idling of diesel engine equipped
vehicles.
If the engine idles too long, the temperature of the
engine coolant will fall below the normal operating
range. Low engine operating temperature causes
several conditions which affect engine operation and
reduce engine life.
The engine should be permitted to go through a
warm-up period. Operate the vehicle at a minimum of
600 rpm during the warm-up period. During this
period and during operation, the following observations
should be made.
2-22
During this warm-up period, check your warning lights
and gages:
•If oil pressure does not begin to rise within
15 seconds of starting, stop the engine and find the
cause. SeeOil Pressure Gage on page 3-37for
more information.
•If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating. SeeEngine
Coolant Temperature Gage on page 3-35for
more information.
•If you have air brakes, the dual-needle air pressure
gage should read at least 115 psi (790 kPa) for
both service systems before you try to move
the vehicle. When air pressure is below 60 psi
(420 kPa), the LOW AIR light will come on and you
will hear a tone alarm. SeeBrake System Warning
Light on page 3-31for more information. If the
pressure does not build up or drops during warm-up,
stop the engine and find the cause before you try
to move the vehicle. Recommended air pressure
before driving is 120 psi (830 kPa). SeeAir
Pressure Gage on page 3-44for more information.
•The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above
idle. If the light does not go out or comes back on
during normal engine operation, have the charging
system checked right away. (This light tells you
if the generator is not charging; it does not reflect
the condition of the battery.) SeeCharging System
Light on page 3-30for more information.
•The voltmeter charge indicator gage tells you the
condition of your battery’s charge. The gage
should be in the center area during engine
operation. The red area on the left indicates an
undercharge condition; the red area on the
right indicates an overcharge. If the gage is in
either red area, have the battery and charging
system checked right away. SeeVoltmeter Gage
on page 3-30for more information.
Notice:Do not allow the engine to operate at low
idle for more than ve minutes. This can cause
low engine operating temperatures which can
affect engine operation and reduce engine life.
Engine idle speed should be increased to 1200 rpm
whenever extended idle is required. Once started,
the engine should be placed under load to allow the
engine coolant temperature to reach 150°F (66°C)
before shutting off the engine.
2-23
Diesel Engine Exhaust Brake
If your vehicle is equipped with a diesel engine,
it may have an exhaust brake, which is located in the
exhaust system.
The exhaust brake is used to help slow the vehicle and
may assist the vehicle’s foundation brakes. The use of
the exhaust brake will assist the braking of the vehicle
and prolong the life of the foundation brake lining
material.
The exhaust brake switch
is located in the instrument
panel switchbank.
Push the bottom of the switch to turn the exhaust brake
on. When you push the top of the switch, the exhaust
brake will turn off.
There is an indicator light on the instrument panel similar
to the symbol on the switch, that will come on when the
exhaust brake is active. SeeExhaust Brake Indicator
Light on page 3-40for more information.When using the exhaust brake, the proper gear range
selection is important. The exhaust brake will be
most effective if the gear range selected is the lowest
possible range that does not allow the engine rpm to go
more than 200 rpm above rated (full load) rpm. If you
have a Caterpillar
®diesel engine, do not exceed
2900 rpm. If you have a DURAMAX®7800 diesel
engine, do not exceed 2550 rpm. If you have a
DURAMAX
®6600 diesel engine, do not exceed
3600 rpm.
If you have an Allison
®1000/2000/2200/2400/2500
series automatic transmission and press this button,
the transmission will downshift to a factory default
setting of fourth gear. To change the default setting,
or for more information on factory default settings,
contact your dealer for assistance.
The accelerator and clutch pedals must be released in
order for the exhaust brake to engage. The exhaust
brake will not function when the cruise control feature
is active with a DURAMAX
®6600 engine, and will
automatically shut off when the anti-lock brake system
is active.
When equipped with a Caterpillar
®diesel engine,
the exhaust brake will become active in cruise control
when you exceed the set speed by 3 mph.
2-25
Two-Speed Rear Axle Electric
Shift Control
If your vehicle is equipped with this feature, you will find
a label on the headliner above the windshield or in
another place near the driver that shows how to use it.
Be sure to follow the directions carefully.
Use the following directions based on the type of shift
control you have.
The rear axle shift control
switch for a manual
transmission is located
on the shift lever.When the switch is up, the rear axle is in the high
range. Push the switch down to change to low range.
The two-speed axle should be in low when you park
the vehicle. You will need to engage the transmission,
even move the vehicle a little, to be sure the axle is
in the low range. Then apply the parking brake, shift into
NEUTRAL and shut off the engine.
Also, always start the vehicle in motion with the
two-speed axle in the low range. To shift up from low
to high, do the following:
1. Move the switch up for the high range,
2. disengage the clutch, and
3. after a brief pause, engage the clutch and then
press down on the accelerator.
To shift down from high to low, do the following:
1. Move the switch down to low,
2. release the accelerator and then quickly
apply it again.
2-26
Air Shift Control
(Automatic Transmission)
The rear axle shift control
switch for an automatic
transmission is located in
the instrument panel
switchbank.
Press the bottom of the switch to get to the low range.
The switch indicator light will come on when the
vehicle is in low range. Press the top of the switch to
return to the high range.
The two-speed axle should be in low range when you
park the vehicle. You will need to engage the
transmission, even moving the vehicle a little, to be sure
the axle is in low range. Then shift into PARK (P),
apply the parking brake and shut off the engine.To shift up from low to high, press the top of the rear
axle shift control switch and press down on the
accelerator. When you shift the axle from high to low,
press the bottom of the switch, release the accelerator
and then quickly press it down again.
To operate off-road or under a heavy load, shift into
low range when the vehicle is standing still and
then operate the transmission normally.
On the highway, with the axle in low range and the
transmission in top gear, you may shift the axle to
high range by raising the switch and releasing
the accelerator momentarily. Re-apply the accelerator
after you shift.
Under light load conditions, first shift the axle into the
high range with the vehicle at a standstill and then
operate the transmission normally.
2-27
Automatic Transmission Operation
We build vehicles with Allison®five and six-speed
automatic transmissions. This part of the manual covers
the basics of these. With these transmissions, you
will find another Allison
®manual in your vehicle that
goes into more detail. On the headliner, in front of and
above the driver, or in some other place near the
driver, you will see a label that describes important
operating facts about the automatic transmission in
your vehicle. Make sure you follow the instructions on
this label.
Be sure to keep your parking brake set until you are
ready to shift into DRIVE (D), and press the brake pedal
while shifting from NEUTRAL (N) or PARK (P) to a
drive gear.
All vehicles equipped with automatic transmissions can
be started in PARK (P), if equipped, or in NEUTRAL (N).
See the Allison
®Transmission Operator’s Manual in
your vehicle for more information about this.
{CAUTION:
It can be dangerous to get out of your vehicle
without the parking brake rmly set. Your
vehicle can roll. If you have left the engine
running, the vehicle can move suddenly. You or
others could be injured. To be sure your vehicle
will not move, even when you are on fairly level
ground, always set the parking brake.
{CAUTION:
Shifting into a drive gear while your engine is
running at high speed is dangerous. Unless
your foot is rmly on the brake pedal, your
vehicle could move very rapidly. You could
lose control and hit people or objects. Do not
shift into a drive gear while your engine is
running at high speed.
2-28
During the first 500 miles (805 km) of vehicle use, start
the vehicle moving in FIRST (1) gear. This allows
the clutch components to wear-in properly.
FIRST (1):With the vehicle at a stop, release the
brake, press the clutch pedal and shift into FIRST (1).
Then, slowly let up on the clutch pedal as you press the
accelerator pedal. Only downshift into FIRST (1)
when the vehicle has come to a complete stop. If the
shift lever will not go into FIRST (1), put the lever
in NEUTRAL and let up on the clutch pedal to fully
engage the clutch. Press the clutch pedal again.
Then, shift into FIRST (1).
SECOND (2):With the vehicle at a stop, release the
brake, press the clutch pedal and shift into SECOND (2).
Then, slowly let up on the clutch pedal as you press
the accelerator pedal. With the vehicle moving, press the
clutch pedal and upshift into SECOND (2) from
FIRST (1) while applying light pressure to the right on
the shifter. Then, slowly let up on the clutch pedal
as you press the accelerator pedal. If you come to a
complete stop and the shift lever will not go into
SECOND (2), put the lever in NEUTRAL and let up on
the clutch pedal to fully engage the clutch. Press
the clutch pedal again. Then, shift into SECOND (2).THIRD (3):Press the clutch pedal and upshift into
THIRD (3). Then, slowly let up on the clutch pedal as
you press the accelerator pedal.
FOURTH (4), FIFTH (5) and SIXTH (6):Upshift into
the higher forward gears the same way as you do
THIRD (3). Slowly let up on the clutch pedal as you
press the accelerator pedal.
NEUTRAL:Use this position when you start or idle
your engine.
REVERSE (R):To back up, press the clutch pedal.
Wait for the vehicle to stop moving and then, shift
to REVERSE (R). Let up on the clutch slowly while
pressing the accelerator pedal. Also, use REVERSE (R),
along with the parking brake, when turning off your
engine and parking your vehicle.
2-31
Eaton®Fuller®Nine and Ten-Speed
Non-Synchronized Manual
Transmissions
If your vehicle has one of these transmissions the
engine rpm and road speed must match when upshifting
and downshifting. The label above the windshield will
tell you the operating basics you need to know.
The following are driving tips.
•Always choose an initial starting gear suitable for
the load and terrain.
•Always use double-clutching procedures when
shifting.
•Never move the range shift lever to the LO speed
gear position after HI range preselection, or
anytime the transmission is in the HI range.
•Never move the range knob or lever with the shift
lever in NEUTRAL while the vehicle is moving.
•Never make a range shift while moving in
REVERSE (R).
Clutch Brake (Vehicles with
Non-Synchronized Transmission)
A clutch brake is used to stop transmission input shaft
rotation so that FIRST (1) or REVERSE (R) gear
selection can be initiated when the vehicle is at a
standstill and the engine is idling.
Press the clutch pedal all the way down to the floorboard
to apply the clutch brake.
When using the clutch brake, disengage the clutch
pedal and shift the transmission into either the initial
starting gear or REVERSE (R). If the tooth-butting
occurs between the clutching teeth, re-engage the clutch
while applying light pressure to the shift lever. This
will provide for a smooth shift into either FIRST (1) or
REVERSE (R) gear.
Notice:Using the clutch brake for shifting into any
gear other than FIRST (1) or REVERSE (R) may
cause premature wear of the clutch brake and make
gear shift effort more difficult. Do not use the
clutch brake for shifting after engaging FIRST (1) or
REVERSE (R).
2-32