Range Inhibit Warning Indicator
If your vehicle has an Allison 1000/2200/2300/2500
series automatic transmission, a lighted bar under the
current gear selected will flash.
If your vehicle has an Allison 3000/3500 series
automatic transmission, the current gear selected on the
pushbutton display will flash.
The flashing bar or gear selection indicates that
transmission range shifts may not occur.
For detailed information on shift inhibit limitations, see
the Allison Automatic Transmission Operator’s Manual in
your vehicle for further information.
Brake System Warning Light
Your vehicle has either hydraulic or air brakes. Each
system has different warning lights.
Hydraulic Brake System Warning
Lights
Vehicles with hydraulic brake systems have two brake
system warning lights on the instrument panel.
If the BRAKE system
warning light comes on, it
means that the fluid
level in the master cylinder
reservoir is low or there
is another problem
with your hydraulic brakes.
When it comes on, you will also hear a warning tone.
The BRAKE system warning light may come on, and the
warning tone may sound, when you’re turning and
braking at the same time. This is normal. See “Hydraulic
Brake Systems” underBraking on page 4-6.
3-33
Transmission Temperature Gage
If you have an automatic
transmission and this
gage, it is located above
the switchbank in the
center of the instrument
panel.
When your ignition is on, the gage shows the
temperature of the transmission oil. A reading in the
warning zone, the red area beginning at 300°F (150°C),
means you must stop driving and check into the
cause. One possible cause is a low oil level in the
transmission.
Notice:If you drive your vehicle with the
transmission temperature gage above normal
operating range, you can damage the transmission.
This could lead to costly repairs that would not
be covered by your warranty. Do not drive your
vehicle while the transmission temperature gage
reading is above normal. See your dealer for service.
Exhaust Brake Indicator Light
If your vehicle is equipped
with an exhaust brake, you
will have this light,
located above the climate
controls in the center
of the instrument panel.
The exhaust brake indicator light will come on and stay
on whenever the diesel engine exhaust brake or
exhaust restrictor is active. For more information, see
Diesel Engine Exhaust Brake on page 2-27andExhaust
Restrictor (Engine Warm-Up) on page 2-22.
3-41
Traction Control System (TCS)
Your vehicle may have a traction control system that
limits wheel spin. This is especially useful in slippery
road conditions. The system operates only if it senses
that one or both of the rear wheels are spinning or
beginning to lose traction. When this happens,
the system applies the brake(s) at the affected wheel(s).
The bottom light on the TCS on/off button will come
on when the TCS is limiting wheel spin. You may feel or
hear the system working, but this is normal. The TCS
will function at speeds up to about 25 mph (42 km/h).
The TCS may operate on dry roads under some
conditions. When this happens, you may notice a
reduction in acceleration. This is normal and doesn’t
mean there’s a problem with your vehicle. Examples of
these conditions include a hard acceleration in a
turn, an abrupt upshift or downshift of the transmission
or driving on rough roads.When the light in the top of the TCS button is on, the
TCS is off and will not limit wheel spin. Adjust your
driving accordingly.
The light in the top of the TCS button will come on if the
TCS is turned off by pressing the TCS on/off button.
The light may also come on if a problem has been
detected in either the traction control system or
the anti-lock brake system.
The traction control system automatically comes on
whenever you start your vehicle. To limit wheel
spin, especially in slippery road conditions, you should
always leave the system on. But you can turn the
traction control system off if you ever need to. You
should turn the system off if your vehicle ever gets stuck
in sand, mud or snow and rocking the vehicle is
required. SeeRocking Your Vehicle to Get It Out on
page 4-32for more information.
4-12
Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in flat or rolling terrain.
Here are some tips that can make your drive through
steep country safer:
•Keep the vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system,
and transmission. These parts can work hard
on mountain roads.
{CAUTION:
If you do not shift down, your brakes could get
so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Shift down
to let your engine assist your brakes on a
steep downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have
to do all the work of slowing down. They could
get so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Always
have your engine running and your vehicle in
gear when you go downhill.
4-26
•Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you go
down a steep or long hill.
•Know how to go uphill. Use lower gears. They help
cool your engine and transmission, and you can
climb the hill better.
•Stay in your own lane when driving on two-lane
roads in hills or mountains. Do not swing wide
or cut across the center of the road. Drive at speeds
that let you stay in your own lane.
•As you go over the top of a hill, be alert. There
could be something in your lane, like a stalled car or
an accident.
•You may see highway signs on mountains that
warn of special problems. Examples are long
grades, passing or no-passing zones, a falling rocks
area, winding roads, and special truck lanes. Be
alert to these and take appropriate action.
Winter Driving
Here are some tips for winter driving:
•Be sure the vehicle is in good shape for winter.
•You may want to put winter emergency supplies in
your vehicle.
Also seeTires on page 5-74.
4-27
If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you do not want to
spin your wheels too fast. The method known as rocking
can help you get out when you are stuck, but you
must use caution.
{CAUTION:
If you let your tires spin at high speed, they
can explode, and you or others could be
injured. And, the transmission or other parts of
the vehicle can overheat. That could cause an
engine compartment re or other damage.
When you are stuck, spin the wheels as little
as possible. Do not spin the wheels above
35 mph (55 km/h) as shown on the
speedometer.
Notice:Spinning your wheels can destroy parts of
your vehicle as well as the tires. If you spin the
wheels too fast while shifting your transmission
back and forth, you can destroy your transmission.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right. That will
clear the area around the front wheels. If you have a
four-wheel-drive vehicle, shift into 4HI. SeeFour-Wheel
Drive on page 2-35. If your vehicle has traction
control, you should turn the traction control system off.
SeeTraction Control System (TCS) on page 4-12.
Then shift back and forth between REVERSE (R) and a
forward gear, or with a manual transmission, between
FIRST (1) or SECOND (2) and REVERSE (R), spinning
the wheels as little as possible. Release the accelerator
pedal while you shift, and press lightly on the
accelerator pedal when the transmission is in gear. By
slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that
may free your vehicle. If that does not get you out
after a few tries, you may need to be towed out. If you
do need to be towed out, seeTowing Your Vehicle
on page 4-37.
4-32
Service............................................................5-3
California Proposition 65 Warning.....................5-3
Doing Your Own Service Work.........................5-4
Engine Fan Breakage.....................................5-5
Fuel................................................................5-6
Gasoline Octane............................................5-6
Gasoline Specifications....................................5-6
Additives.......................................................5-6
Diesel Engine Fuel.........................................5-7
What Fuel to Use...........................................5-8
Very Cold Weather Operation.........................5-10
Water in Fuel...............................................5-10
Running Out of Fuel.....................................5-17
Fuel Filter Replacement.................................5-18
Fuels in Foreign Countries.............................5-19
Filling the Tank............................................5-20
Filling a Portable Fuel Container.....................5-21
Checking Things Under the Hood....................5-22
Hood Latches...............................................5-22
Engine Oil (Caterpillar
®Diesel Engine).............5-24
Engine Oil (DURAMAX®Diesel)......................5-24
Engine Oil (Gasoline Engine)..........................5-28
Engine Oil Life System (Gasoline Engine)........5-31
Engine Oil Life System (DURAMAX
®Diesel).....5-33
Engine Oil Life System
(Caterpillar
®Diesel Engine).........................5-34Engine Air Cleaner/Filter................................5-35
Automatic Transmission Fluid.........................5-36
Manual Transmission Fluid.............................5-37
Engine Coolant
(Gas and DURAMAX
®Engines)...................5-38
Engine Coolant (Caterpillar®Diesel Engines).....5-40
Coolant Surge Tank Pressure Cap..................5-40
Engine Overheating.......................................5-40
Cooling System
(Gas and DURAMAX
®Engines)...................5-42
Engine Fan Noise.........................................5-47
Power Steering Fluid.....................................5-47
Windshield Washer Fluid................................5-48
Brakes........................................................5-49
Battery........................................................5-58
Jump Starting...............................................5-59
Rear Axle.......................................................5-64
Rear Axle Shift Motor....................................5-65
Four-Wheel Drive............................................5-65
Front Axle......................................................5-66
Noise Control System.....................................5-67
Tampering with Noise Control System
Prohibited.................................................5-67
Bulb Replacement..........................................5-68
Windshield Wiper Blade Replacement..............5-69
Section 5 Service and Appearance Care
5-1
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors
recommends against the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs
and the performance of the emission control system may
be affected. The malfunction indicator lamp may turn
on. If this occurs, return to your authorized GM dealer for
service.Diesel Engine Fuel
For the Caterpillar®diesel, see the Caterpillar®
Operation & Maintenance Manual for information
concerning fuel usage.
Notice:Diesel fuel or fuel additives not
recommended in this manual could damage your
fuel system and engine. Your warranty would
not cover this damage. And:
Diesel fuel that has been mixed with engine oil
or automatic transmission uid could damage
your engine and emission controls.
Aftermarket diesel fuel additives are not tested
by General Motors. Some additives, particularly
those which contain alcohol or water
emulsi ers, may damage your fuel system. If
you believe that unique circumstances call for a
fuel additive to be used, consult your dealer
for advice.
If you ever run out of diesel fuel, it can be
difficult to restart your engine. To avoid
this, never let your tank get empty.
If gasoline is ever accidentally added to the fuel
tank, to avoid severe engine damage, do not run the
engine until the fuel tank can be drained.
If you run out of fuel,Running Out of Fuel on page 5-17
tells you how to restart your engine.
5-7