Page 253 of 386

5-28
If You're 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 don't want to spin your
wheels too fast. The method known as ªrockingº can
help you get out when you're 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 fire or other damage. When you're
stuck, spin the wheels as little as possible. Don't
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 your steering wheel left and right. That will
clear the area around your front wheels. If your vehicle
has traction control, you should turn your traction
control system off. See ªTraction Control Systemº in the
Index. 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
doesn't get you out after a few tries, you may need to be
towed out. If you do need to be towed out, see ªTowing
Your Vehicleº in the Index.
Page 255 of 386

6-
6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-4 Fuel (Gasoline Engine)
6
-5 Diesel Fuel Requirements and Fuel System
6
-15 Fuels in Foreign Countries (Gasoline Engines)
6
-15 Filling Your Tank
6
-17 Filling a Portable Fuel Container
6
-18 Checking Things Under the Hood
6
-20 Noise Control System
6
-21 Engine Oil (Gasoline Engines)
6
-27 Engine Oil (Caterpillar Diesel Engines)
6
-27 Engine Oil (DURAMAX Diesel)
6
-30 Engine Air Cleaner/Filter
6
-32 Automatic Transmission Fluid
6
-32 Manual Transmission Fluid
6
-34 Rear Axle
6
-34 Rear Axle Shift Motor (Option)
6
-35 Engine Coolant
6
-38 Engine Coolant (Caterpillar Diesel Engine)6
-38 Surge Tank Pressure Cap
6
-39 Power Steering Fluid
6
-40 Windshield Washer Fluid
6
-41 Brakes
6
-52 Battery
6
-54 Other Service Items
6
-58 Tires
6
-67 Appearance Care
6
-68 Cleaning the Inside of Your Vehicle
6
-71 Cleaning the Outside Your Vehicle
6
-75 GM Vehicle Care/Appearance Materials
6
-76 Vehicle Identification Number (VIN)
6
-76 Service Statement
6
-77 Service Parts Identification Label
6
-77 Electrical System
6
-86 Capacities and Specifications
6
-90 Normal Maintenance Replacement Parts
Page 293 of 386

6-39
Power Steering Fluid
See your Maintenance Schedule for 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 isn't warm, you probably won't get
an accurate reading.
If the fluid level is
between the MIN and
MAX marks, you have
enough. If you need
fluid, add only enough
of the proper fluid to
bring it into view in
the sight glass.If your power steering fluid level is low, this can cause
the BRAKE or service brake soon warning lights to
come on. 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 though, see
ªHydraulic Brake Warning Lightsº in the Index.
What to Use
To determine what kind of fluid to use, see
ªRecommended Fluids and Lubricantsº in the Index.
NOTICE:
When adding power steering fluid or making a
complete fluid change, always use the proper
fluid. Failure to use the proper fluid can cause
leaks and damage hoses and seals.
Page 303 of 386
6-49
ITEM NO. ITEM REMARKS
1
Brake Camshaft One fitting each (apply sparingly).
2 Steering Column Slip Joint* One fitting.
3 Steering Drag Link Ends One fitting at each end.
4 Pivot Points and Hinges Apply chassis lubricant
5 Pivot Points and Hinges Apply chassis lubricant.
6
Slack Adjuster One fitting.
7 Brake Cam Roller Pins at
interface of pin and shoe Apply engine oil.
8 Front Steering Knuckles
One fitting each side, lower bushing (hand
-operated
grease gun only). Hand
-pack upper bearing.
9 Front Wheel Bearings
Hand
-pack or lubricate.
10 Steering Tie Rod Ends One fitting each end.
11 Spring Slip Pads*
(Multi
-Leaf Only)Apply chassis lubricant.
Page 316 of 386
6-62 Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned at the factory
to give you the longest tire life and best overall
performance.
Proper front wheel alignment must be maintained in
order to ensure efficient steering, good directional
stability, and prevent abnormal tire wear. If you notice
unusual tire wear or your vehicle is pulling one way or
the other, the alignment may need to be reset. If you
notice your vehicle vibrating when driving on a smooth
road, your wheels may need to be balanced.
Tightening the Wheel Nuts
CAUTION:
Wheel nuts that are not tight can work loose. If
all the nuts on a wheel come off, the wheel can
come off the vehicle, causing a crash. All wheel
nuts must be properly tightened. Follow the rules
in this section to be sure they are.
This section lets you know how often to check the
tightness of the wheel nuts on your vehicle and how
tight they must be.
First, use these pictures to decide what kind of wheels
you have.
Page 346 of 386
6-92
Engine 7.2L 8.1L 7.8L 6.6L
Power Steering
Fluid FilterGM Part
No. 88892858GM Part
No. 88892858GM Part
No. 88892858GM Part
No. 88892858
Secondary
Fuel FilterCAT
1R0751GM Part
No. 25055052GM Part
No. 15098649
Pressure Caps
RC
-54GM Part
No. 15997145GM Part
No. 15075118GM Part
No. 15075118
*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.
Page 352 of 386

7-6
15,000 Miles (24 000 km)
Gasoline Engine Only: Check Oil Life System.
If engine oil and filter are changed, reset system.
See ªEngine Oilº in the Index. (3)(9)
Chassis lubrication service (or every 6 months,
whichever occurs first). (12)
Check fluid levels (or every 3 months, whichever
occurs first). (1)(6)
DURAMAX Diesel Only: Replace fuel filter.
Steering system service. (13)
Front and rear suspension service. (14)
Spring
-to-axle U-bolts and shackle bolts
service. (16)
Exhaust system service (or every 6 months,
whichever occurs first). (3)(4)(17)
Wheels and tires service. (15)
Hydraulic brake service (or every 6 months,
whichever occurs first). (7)(46)
Parking brake service (or every 6 months, whichever
occurs first). (8)
Thermostatically controlled engine cooling fan
service. (4)(20)
Shields and underhood insulation service. (4)(5)(21)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
20,000 Miles (32 000 km)
DURAMAX Diesel Only: Change engine oil
and filter (or every 12 months, whichever occurs
first). (2)(3)
Air compressor dry element pleated paper air strainer
service (or every 2 months or every 800 hours,
whichever occurs first).
22,500 Miles (36 000 km)
Gasoline Engine Only: Check Oil Life System.
If engine oil and filter are changed, reset system.
See ªEngine Oilº in the Index. (3)(9)
Check fluid levels (or every 3 months, whichever
occurs first). (1)(6)
Chassis lubrication service (or every 6 months,
whichever occurs first). (12)
Inspect door hinge pins and bushings and replace
as necessary.
Cooling system service. Clean the cooling system
filler cap with clean water, clean the core, pressure
test the cap and the system for proper pressure
capability and inspect condition of cooling and
heater hoses and clamps. Replace hoses if cracked,
swollen or damaged.
Page 353 of 386

7-7
Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever
hubs are removed). (23)(46)
Wheels and tires service. (15)
Parking brake service (or every 6 months, whichever
occurs first). (8)
Air intake system service (or every 24 months,
whichever occurs first). (4)(5)(24)
Evaporative Control System service (if equipped) (or
every 24 months, whichever occurs first). (3)(26)
Rear axle air shift motor service. (11)
Air brake service (or every 6 months, whichever
occurs first). (39)
Air brake automatic slack adjuster service
(or every 500 hours, whichever occurs first). (40)
Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
Clean air brake application valve (or every 3 months,
or every 300 hours, whichever occurs first); lubricate
linkage.
Air brake chamber service (or every 2 months,
whichever occurs first). (41)Trailer brake hand control valve service (or every
3 months, or every 900 hours, whichever
occurs first). (42)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
30,000 Miles (48 000 km)
Gasoline Engine Only: Check Oil Life System.
If engine oil and filter are changed, reset system.
See ªEngine Oilº in the Index. (3)(9)
DURAMAX Diesel Only: Change engine oil
and filter (or every 12 months, whichever occurs
first). (2)(3)
Check fluid levels (or every 3 months, whichever
occurs first). (1)(6)
DURAMAX Diesel Only: Replace fuel filter.
Chassis lubrication service (or every 6 months,
whichever occurs first). (12)
Replace fuel filter(s) (or every 12 months, whichever
occurs first). (3)
Steering system service. (13)
Front and rear suspension service. (14)
Spring
-to-axle U-bolts and shackle bolts
service. (16)
Exhaust system service (or every 6 months,
whichever occurs first). (3)(4)(17)
(Continued)