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
Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number, or specification may be obtained from
your dealer.
Usage Fluid/Lubricant
Engine Oil
(Gasoline
Engine)Engine oil which meets GM
Standard GM6094M and displays
the American Petroleum Institute
Certified for Gasoline Engines
starburst symbol. GM Goodwrench
®
oil meets all the requirements for
your vehicle. To determine the
proper viscosity for your vehicle’s
engine, see “Engine Oil” in
the Index.
Engine Oil
(DURAMAX
®
Diesel Engine)Engine oil with the letters CI-4 or
CH-4 is best for your vehicle. The
CI-4 or CH-4 designation may
appear either alone or in
combination with other API
designations, such as API CI-4/SL.
These letters show American
Petroleum Institute levels of quality.
To determine the preferred viscosity
for your vehicle’s diesel engine, see
“Engine Oil” in the Index.
Engine Oil
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine oil
recommendations.
Usage Fluid/Lubricant
Engine Coolant
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine
coolant recommendations.
Engine Coolant
(Gasoline
Engine &
DURAMAX
®
Diesel)50/50 mixture of clean, drinkable
water and use only DEX-COOL
®
Coolant. See “Engine Coolant” in
the Index.
Hydraulic Brake
SystemDelco
®Supreme 11 Brake Fluid or
equivalent DOT-3 brake fluid.
Windshield
Washer SolventGM Optikleen
®Washer Solvent.
Clutch Bearing
LubricantClutch Bearing Lubricant
(GM Part No. 12378484 or
equivalent NLGI #3 consistency).
Exhaust Brake
Ball Joint Cap
LubricantHigh-Temperature Grease
(GM Part No. U.S. 1051344, in
Canada 903037) or NLGI #3
consistency.
Power Steering
SystemDEXRON
®-III Automatic
Transmission Fluid. Look for
“Approved for the H-Specification”
on the label.
Manual
Transmission
(Except ZF
6-Speed)Synthetic Manual Transmission Fluid
(GM Part No. U.S. 12345724, in
Canada 10953510).
6-32
F
Filter
Engine Air Cleaner......................................5-33
Filter Minder Gage..........................................3-43
Finish Damage...............................................5-85
Fixed Mast Antenna........................................3-59
Flat Tire........................................................5-78
Fluid
Automatic Transmission................................5-34
Manual Transmission....................................5-35
Power Steering...........................................5-45
Windshield Washer......................................5-46
Four-Wheel Drive....................................2-33, 5-62
Front Axle......................................................5-63
Front Wheel Bearings with Oil-Filled Hubs..........5-69
Fuel............................................................... 5-6
Additives...................................................... 5-6
Diesel Engine Fuel........................................ 5-7
Filling a Portable Fuel Container....................5-19
Filling Your Tank..........................................5-18
Filter..........................................................5-66
Filter Replacement.......................................5-16Fuel (cont.)
Fuels in Foreign Countries............................5-17
Gage.........................................................3-42
Gasoline Octane........................................... 5-6
Gasoline Specifications.................................. 5-6
Primary Filter and Water Separator................5-67
Running Out of Fuel....................................5-15
Secondary Filter and Water
Separator/Heater......................................5-68
Very Cold Weather Operation........................5-10
Water in Fuel..............................................5-10
Water in Warning Light.................................3-43
What Fuel to Use.......................................... 5-8
Fuses
Fuses and Circuit Breakers...........................5-89
Instrument Panel Fuse Block.........................5-89
Underhood Fuse Block.................................5-92
Windshield Wiper.........................................5-88
6
Other Service Items (cont.)
Primary Fuel Filter and Water Separator.........5-67
Secondary Fuel Filter and Water Separator/
Heater....................................................5-68
Other Warning Devices...................................... 3-6
Outlet Adjustment............................................3-23
Outside
Convex Mirrors............................................2-46
Heated Mirrors............................................2-46
Manual Mirrors............................................2-45
Power Mirrors.............................................2-45
Overspeed Warning Light.................................3-39
Owners, Canadian............................................... ii
P
Parking.........................................................2-38
Air Brake....................................................2-40
Hydraulic Brakes.........................................2-38
Over Things That Burn.................................2-43
Propshaft Brake Burnish Procedure................2-39
Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-27
Part C - Recommended Fluids and Lubricants....6-32
Part D - Maintenance Record...........................6-34
Passing.........................................................4-13Power
Accessory Outlets........................................3-19
Door Locks.................................................. 2-7
Electrical System.........................................5-89
Reduced Engine Light..................................3-41
Steering Fluid.............................................5-45
Windows...................................................... 2-9
Propshaft Brake Burnish Procedure...................2-39
Q
Questions and Answers About Safety Belts.........1-13
R
Radios..........................................................3-44
AM-FM Radio.............................................3-45
Care of Your Cassette Tape Player................3-58
Care of Your CD Player...............................3-59
Care of Your CDs........................................3-59
Radio with Cassette.....................................3-48
Radio with CD............................................3-53
Setting the Time..........................................3-45
Theft-Deterrent............................................3-57
Understanding Reception..............................3-57
Range Inhibit Warning Indicator........................3-31
10