Ignition Positions
With your key in the ignition switch, you can turn it to
five different positions.
A (ACCESSORY):This position allows you to use
things like the radio, power windows and the windshield
wipers when the engine is off. To get into ACCESSORY,
push in the key and turn it toward you. Your steering
wheel will remain locked, just as it was before you
inserted the key.
B (LOCK):This position locks your ignition, steering
wheel and transmission. It is a theft-deterrent feature.
You will only be able to remove your key when the
ignition is turned to LOCK.C (OFF):This position lets you turn off the engine but
still turn the steering wheel. It does not lock the
steering wheel like LOCK. Use OFF if you must have
your vehicle in motion while the engine is off.
D (RUN):This is the position for driving.
E (START):This position starts your engine.
Engine Starter Over-Crank
Protection
Your vehicle may have an engine starter over-crank
protection system. If the starter motor overheats and
shuts off due to over-cranking, the motor must cool down
before it will reset and allow starter operation. It can take
up to six minutes before the starter will work again.
Starting the Gasoline Engine
Engines start differently. The 8th digit of your Vehicle
Identification Number (VIN) shows the code letter for your
engine. SeeVehicle Identi cation Number (VIN) on
page 5-87. Follow the proper steps to start the engine.
To start a diesel engine, seeStarting the Diesel Engine
on page 2-14.
2-12
Charging System Light
The charging system light
may be located in the
instrument panel cluster, or
with the auxiliary warning
lights in the center of
the instrument panel.
It should come on briefly when you turn on the ignition,
before the engine is running, as a check to show
that it is working.
If it stays on, or comes on while you are driving, have
your vehicle checked right away. You could have a loose
generator drive belt or some other problem.
Driving while this light is on will drain your battery. If you
must drive a short distance with the light on, turn off
your radio and other accessories. Sustained driving with
a generator failure could result in a lack of back-up
braking if the engine quits or the power steering pump
should fail.
Voltmeter Gage
When your engine is
running, the voltmeter
gage shows the charging
system voltage.
Readings in either warning zone indicate a possible
problem in the electrical system.
Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system may not be able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself because higher
engine speeds allow the charging system to create
maximum power.
You can only drive a short time on the battery. Be sure
to shut off the radio, the fan or any unnecessary
accessories and have the system serviced.
3-30
Your Driving, the Road, and Your Vehicle..........4-2
Defensive Driving...........................................4-2
Drunken Driving.............................................4-2
Control of a Vehicle........................................4-5
Braking.........................................................4-5
Hydraulic Brake Systems.................................4-6
Anti-Lock Brake System (ABS).........................4-6
Braking in Emergencies...................................4-8
Trailer Brake Hand Control Valve......................4-8
Rear Axle Differential Lock Control....................4-9
Traction Control System (TCS).......................4-10
Steering......................................................4-11
Off-Road Recovery.......................................4-13
Passing.......................................................4-13
Loss of Control.............................................4-15
Driving at Night............................................4-16Driving in Rain and on Wet Roads..................4-18
City Driving..................................................4-21
Freeway Driving...........................................4-22
Highway Hypnosis........................................4-23
Hill and Mountain Roads................................4-24
Winter Driving..............................................4-26
If Your Vehicle is Stuck in Sand, Mud,
Ice or Snow..............................................4-30
Rocking Your Vehicle to Get It Out.................4-30
Tow Hooks..................................................4-31
Loading Your Vehicle....................................4-32
Adding a Snow Plow or Similar Equipment.......4-34
Towing..........................................................4-35
Towing Your Vehicle.....................................4-35
Trailer Connections.......................................4-37
Power Take-Off (PTO)...................................4-38
Section 4 Driving Your Vehicle
4-1
Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by heavy
braking — rather than keeping pace with traffic. This is
a mistake. Your brakes may not have time to cool
between hard stops. Your brakes will wear out much
faster if you do a lot of heavy braking. If you keep pace
with the traffic and allow realistic following distances,
you will eliminate a lot of unnecessary braking.
That means better braking and longer brake life.
If your engine ever stops while you are driving, brake
normally but do not pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.
Hydraulic Brake Systems
If your engine stops running, or if your primary brake
system stops working, your vehicle has a reserve power
assist system to help you slow down. Just slowly and
steadily apply the brake pedal until you can safely get off
the road. The pedal will seem harder to push down.
Do not pump the pedal; the system will not work well or
at all that way.You may find that the steering wheel seems hard to turn
when you are turning and braking at the same time.
Also, the primary brake warning light may come on and
the warning tone may sound. This is normal because
the main hydraulic brake system and power steering
both use the power steering pump. If this ever happens,
let up on the brake pedal a little. When you let up on
the brake pedal in that situation, it lets the steering get a
little more help from the pump.
Anti-Lock Brake System (ABS)
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You
may hear a momentary motor or clicking noise while
this test is going on. This is normal.
If there is a problem with
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-34.
4-6
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer but
it will take much more effort.
On vehicles with hydraulic brakes, the power steering
and main hydraulic brake system both use the
power steering pump. SeeBraking on page 4-5.
Steering Tips
Driving on Curves
It is important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents mentioned on
the news happen on curves. Here is why:
Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves.
The traction of the tires against the road surface makes
it possible for the vehicle to change its path when
you turn the front wheels. If there is no traction, inertia
will keep the vehicle going in the same direction. If
you have ever tried to steer a vehicle on wet ice, you
will understand this.The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle at
which the curve is banked, and your speed. While
you are in a curve, speed is the one factor you
can control.
Suppose you are steering through a sharp curve.
Then you suddenly accelerate. Both control
systems — steering and acceleration — have to do
their work where the tires meet the road. Adding
the sudden acceleration can demand too much of those
places. You can lose control. SeeTraction Control
System (TCS) on page 4-10.
What should you do if this ever happens? Ease up on
the accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds
are based on good weather and road conditions. Under
less favorable conditions you will want to go slower.
If you need to reduce your speed as you approach
a curve, do it before you enter the curve, while your front
wheels are straight ahead.
Try to adjust your speed so you can “drive” through the
curve. Maintain a reasonable, steady speed. Wait to
accelerate until you are out of the curve, and then
accelerate gently into the straightaway.
4-11
Service............................................................5-3
Doing Your Own Service Work.........................5-4
Two Safety Cautions about 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.....................................5-15
Fuel Filter Replacement.................................5-16
Fuels in Foreign Countries.............................5-17
Filling the Tank............................................5-18
Filling a Portable Fuel Container.....................5-19
Checking Things Under the Hood....................5-20
Hood Latches...............................................5-20
Engine Oil (Caterpillar
®Diesel Engine).............5-22
Engine Oil (DURAMAX®Diesel)......................5-22
Engine Oil (Gasoline Engine)..........................5-26
Engine Oil Life System (Gasoline Engine)........5-29
Engine Oil Life System (DURAMAX
®Diesel).....5-31
Engine Oil Life System (Caterpillar®
Diesel Engine)..........................................5-32Engine Air Cleaner/Filter................................5-33
Automatic Transmission Fluid.........................5-34
Manual Transmission Fluid.............................5-35
Engine Coolant (Gas and
DURAMAX
®Engines).................................5-36
Engine Coolant (Caterpillar®Diesel Engines).....5-38
Coolant Surge Tank Pressure Cap..................5-38
Engine Overheating.......................................5-38
Cooling System (Gas and
DURAMAX
®Engines).................................5-40
Engine Fan Noise.........................................5-45
Power Steering Fluid.....................................5-45
Windshield Washer Fluid................................5-46
Brakes........................................................5-47
Battery........................................................5-55
Jump Starting...............................................5-56
Rear Axle.......................................................5-60
Rear Axle Shift Motor....................................5-62
Four-Wheel Drive............................................5-62
Front Axle......................................................5-63
Noise Control System.....................................5-64
Tampering with Noise Control System
Prohibited.................................................5-64
Bulb Replacement..........................................5-65
Windshield Wiper Blade Replacement..............5-65
Section 5 Service and Appearance Care
5-1
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
Power Steering Fluid
SeeScheduled Maintenance on page 6-5to determine
when to check your power steering fluid.
How To Check Power Steering Fluid
Check your power steering fluid only when the engine is
warm. If the engine is not warm, you probably will not
get an accurate reading.
If the fluid level is between the MIN (Minimum) and
MAX (Maximum) marks, you have enough. If you need
fluid, add only enough of the proper fluid to bring it
in between the MIN and MAX marks.
If your power steering fluid level is low, this can cause
the brake or service brakes soon warning lights to come
on. In addition, the steering effort and emergency
brake distance could increase.
If either light remains on after you have added power
steering fluid to the proper level, then shut off the engine
for 10 seconds. This should reset the brake warning
lights. If one or both lights stay on, see “Hydraulic Brake
System Warning Lights” underBrake System Warning
Light on page 3-31for more information.
What to Use
To determine what kind of fluid to use, seePart C:
Recommended Fluids and Lubricants on page 6-32.
Notice:When adding power steering uid or
making a complete uid change, always use the
proper uid. Failure to use the proper uid can
cause leaks and damage hoses and seals.
5-45
Part GM Part Number ACDelco®Part Number
Fuel Filter
6.6L 97385488 TP1298A
7.2L — 915 Primary**
7.8L 94392474 —
8.1L — GF626*
Power Steering Fluid Filter 88892858 —
Pressure Caps
6.6L; 7.8L 15075118 —
7.2L — —
8.1L 15997145 —
Secondary Fuel Filter
6.6L — —
7.2L — 1R0751††
7.8L 15098649 —
8.1L 25055052 —
Spark Plugs
6.6L — —
7.2L — —
7.8L — —
8.1L 12578277 41-983
*Optional Davco (K28) D350921 spin-on type filter located on driver’s side frame rail.
**Optional Cold Weather (KUK) Racor B6484GM spin-on type filter located on driver’s side frame rail.
***Optional air filter (GM Part No. 88937525) for C6/C7/C8 Models. Fits inside standard size filter
(GM Part No. 88937548) listed previously.
†Donaldson part number.
††CAT part number.
See the Allison Transmission
®Operator’s Manual in your vehicle for external filter part numbers and information.
5-101