
❑Replace fuel filter(s) (or every 12 months, whichever
occurs first).(2)
❑Steering system service.(12)
❑Front and rear suspension service.(13)
❑Spring-to-axle U-bolts and shackle bolts service.(15)
❑Exhaust system service (or every 6 months,
whichever occurs first).(2) (3) (16)
❑Inspect door hinge pins and bushings and replace as
necessary.
❑Wheel bearing (grease type) service (and whenever
hubs are removed).(22) (36)
❑Wheels and tires service.(14)
❑Hydraulic brake service (or every 6 months,
whichever occurs first).(6) (36)
❑Parking brake service (or every 6 months, whichever
occurs first).(21)
❑Air brake service (or every 6 months, whichever
occurs first).(32)
❑Air brake automatic slack adjuster service (or every
500 hours, whichever occurs first).(33)
❑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).(34)
❑Air brake system valve service (or every 3 months,
or every 900 hours, whichever occurs first).(37)
❑C600, C700, and C800 Gasoline Engines
Only: Engine drive belts service (or every 12 months,
whichever occurs first).(17)
❑Thermostatically controlled engine cooling fan
service.(3) (19)
❑Shields and underhood insulation service.(3) (4) (20)
❑Rear axle air shift motor service.(10)
❑Air intake system service (or every 24 months,
whichever occurs first).(3) (4) (23)
❑Evaporative Control System service, if equipped, (or
every 24 months, whichever occurs first).(2) (24) †
❑Air compressor dry element pleated paper air strainer
service (or every 2 months or every 800 hours,
whichever occurs first).
6-19

(11)= Chassis Lubrication Service: Lubricate all grease
fittings in front suspension, front axle, and steering
linkage. DO NOT lubricate kingpin bushings with
air pressure equipment; instead, use a hand grease gun
to ensure complete purge and eliminate sealer cap
distortion. Front axle tie rod ends, both upper and lower
kingpin fittings, and both steering linkage relay rod
ends should be greased with the vehicle loaded on the
ground and wheels turned straight ahead, NOT with
the vehicle on a hoist. Apply kingpin bushing lubricant to
both upper and lower kingpin grease fittings until new
lubricant purges from between the upper shim pack and
thrust bearing. Lubricate transmission and shift
linkage, hood latches and hood hinges, parking brake
lever pivot, clevis pins and linkage, disc brake caliper
rails, clutch linkage and release bearing (if equipped),
bearing pads, propshaft universal joints, brake camshaft
bracket, slack adjusters, pedal shaft, clutch cross
shaft, clutch pedal springs, and clutch cable bushing at
transmission. Lubricate suspension, axle, and steering
linkage more often when operating under dusty or
muddy conditions and in excessive off-road use.
Frequently power-washed vehicles will require more
frequent lubrication.(12)= Check steering system:
•Look for damaged, loose, or missing parts. Inspect
the steering linkage relay rod and tie rod ends for
looseness or lack of lubricant. Also look for
parts showing signs of wear or lack of lubrication.
Replace parts as needed. Also check steering gear
mounting bolts, pitman arm nut, gear housing
upper cover and side cover attaching bolts, steering
column mounting bolts and cardan joint clamp
bolts; tighten if necessary. See the service manual.
•Inspect power steering hoses, tubes, and fittings for
leaks. Hoses and lines must not be twisted, kinked,
or tightly bent. Make sure clips, clamps, supporting
tubes, and hoses are in place and properly
secured.
•Check steering gear for leakage around pitman
shaft and housing. If leakage is evident (lubricant
oozing out, not just oily film), leak should be
corrected immediately.
(13)= Check front and rear suspension. Look for
damaged, loose, or missing parts or parts showing signs
of wear or lack of lubrication. Replace parts as
needed.
6-24

Reporting Safety Defects to the
Canadian Government
If you live in Canada, and you believe that your vehicle
has a safety defect, you should immediately notify
Transport Canada, in addition to notifying General
Motors of Canada Limited. You may call them at
1-800-333-0510 or write to:
Transport Canada
Place de Ville Tower C
330 Sparks Street
Ottawa, Ontario K1A 0N5
Reporting Safety Defects to
General Motors
In addition to notifying NHTSA (or Transport Canada) in
a situation like this, we certainly hope you’ll notify us.
Please call us at 1-800-862-4389, or write:
GM Medium Duty Truck
Customer Assistance Center
P.O. Box 44947
Detroit, MI 48244
In Canada, please call us at 1-800-263-3777 (English)
or 1-800-263-7854 (French). Or, write:
General Motors of Canada Limited
Customer Communication Centre, 163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
Service Publications Ordering
Information
Service Manuals
Service Manuals have the diagnosis and repair
information on engines, transmission, axle suspension,
brakes, electrical, steering, body, etc.
Transmission, Transaxle, Transfer
Case Unit Repair Manual
This manual provides information on unit repair service
procedures, adjustments, and specifications for
GM transmissions, transaxles, and transfer cases.
Service Bulletins
Service Bulletins give technical service information
needed to knowledgeably service General Motors cars
and trucks. Each bulletin contains instructions to
assist in the diagnosis and service of your vehicle.
In Canada, information pertaining to Product Service
Bulletins can be obtained by contacting your General
Motors dealer or by calling 1-800-GM-DRIVE
(1-800-463-7483).
7-11

A
Accessory Power Outlet(s)...............................3-19
Adding a Snow Plow or Similar Equipment.........4-36
Adding Equipment to Your Airbag-Equipped
Vehicle.......................................................1-61
Additives, Fuel................................................. 5-6
Add-On Electrical Equipment............................5-92
Air Brake.......................................................2-42
Air Cleaner/Filter, Engine.................................5-35
Air Conditioning..............................................3-20
Air Conditioning System...................................5-74
Air Pressure Gage..........................................3-47
Air Shift Control..............................................2-29
Air Suspension...............................................2-44
Air Suspension Seats........................................ 1-6
Airbag
Off Light.....................................................3-30
Readiness Light..........................................3-29
Airbag Sensing and Diagnostic Module (SDM)........ 7-6
Airbag System................................................1-50
Adding Equipment to Your Airbag-Equipped
Vehicle...................................................1-61
Airbag Off Switch........................................1-58
How Does an Airbag Restrain?......................1-56
Servicing Your Airbag-Equipped Vehicle..........1-61
What Makes an Airbag Inflate?......................1-56
What Will You See After an Airbag Inflates?....1-56Airbag System (cont.)
When Should an Airbag Inflate?....................1-55
Where Are the Airbags?...............................1-54
AM-FM Radio.................................................3-50
Antenna, Fixed Mast.......................................3-67
Anti-Lock Brake System (ABS)........................... 4-8
Anti-Lock Brake, System Warning Light..............3-35
Anti-Lock Brakes, Trailer System
Warning Light.............................................3-36
Appearance Care
Aluminum or Chrome-Plated Wheels..............5-89
Care of Safety Belts....................................5-86
Chemical Paint Spotting...............................5-90
Cleaning Exterior Lamps/Lenses....................5-87
Cleaning the Inside of Your Vehicle................5-83
Fabric/Carpet..............................................5-85
Finish Care.................................................5-87
Finish Damage............................................5-89
Instrument Panel, Vinyl, and Other
Plastic Surfaces.......................................5-86
Sheet Metal Damage...................................5-89
Tires..........................................................5-89
Underbody Maintenance...............................5-90
Vehicle Care/Appearance Materials................5-90
Washing Your Vehicle...................................5-87
Weatherstrips..............................................5-86
Windshield and Wiper Blades........................5-88
Ashtray(s)......................................................3-20
1

Range Inhibit Warning Indicator........................3-33
Reading Lamps..............................................3-17
Rear Axle......................................................5-64
Differential Lock Control...............................4-11
Shift Motor.................................................5-65
Two-Speed Electric Shift Control....................2-28
Rear Heating System......................................3-24
Rear Outside Passenger Positions, Safety Belts....1-25
Rear Seat Operation......................................... 1-8
Rearview Mirrors.............................................2-47
Reduced Engine Power Light............................3-42
Remote Keyless Entry System............................ 2-3
Remote Keyless Entry System, Operation............ 2-4
Reporting Safety Defects
Canadian Government..................................7-11
General Motors...........................................7-11
United States Government............................7-10
Restraint System Check
Checking the Restraint Systems....................1-62
Replacing Restraint System Parts
After a Crash..........................................1-63
Right Front Passenger Position, Safety Belts......1-23
Roadside
Assistance Program....................................... 7-5
Rocking Your Vehicle to Get it Out....................4-32
Running Out of Fuel........................................5-17
Running the Engine While Parked.....................2-46S
Safety Belt
Reminder Light............................................3-28
Reminder Tone............................................3-28
Safety Belts
Care of ......................................................5-86
Center Passenger Position............................1-24
Driver Position............................................1-15
How to Wear Safety Belts Properly................1-14
Questions and Answers About Safety Belts.....1-14
Rear Outside Passenger Positions.................1-25
Right Front Passenger Position......................1-23
Safety Belt Extender....................................1-28
Safety Belt Use During Pregnancy.................1-23
Safety Belts Are for Everyone......................... 1-9
Shoulder Belt Height Adjuster........................1-22
Safety Warnings and Symbols.............................. iii
Scheduled Maintenance..................................... 6-5
Scheduled Maintenance Supplements.................. 6-4
Seats
Air Suspension Seats.................................... 1-6
Bucket Seats................................................ 1-2
Rear Seat Operation...................................... 1-8
Split Bench Seat........................................... 1-6
11

Securing a Child Restraint
Center Rear Seat Position (Crew Cab)
or Center Front Position............................1-44
Rear Outside Seat Position...........................1-42
Right Front Seat Position..............................1-46
Service........................................................... 5-3
California Proposition 65 Warning.................... 5-3
Doing Your Own Work................................... 5-4
Engine Fan Breakage.................................... 5-5
Engine Soon Light.......................................3-38
Publications Ordering Information...................7-11
Transmission Warning Light..........................3-32
Servicing Your Airbag-Equipped Vehicle..............1-61
Setting the Time.............................................3-49
Sheet Metal Damage.......................................5-89
Shoulder Belt Height Adjuster...........................1-22
Signals, Turn and Lane-Change.......................... 3-8
Sliding Rear Windows.....................................2-10
Snow Plow....................................................4-36
Specifications, Capacities.................................5-99
Speedometer..................................................3-27
Split Bench Seat.............................................. 1-6
Starting Your Diesel Engine..............................2-15
Starting Your Gasoline Engine..........................2-13
Steering........................................................4-13
Steering Wheel, Tilt Wheel................................. 3-7Storage Areas................................................2-49
Center Console Storage Area........................2-49
Stuck in Sand, Mud, Ice, or Snow.....................4-32
Sun Visors.....................................................2-10
Suspension, Air..............................................2-44
Switchbanks, Instrument Panel..........................3-18
T
Tachometer....................................................3-27
Theft-Deterrent, Radio.....................................3-64
Tilt Wheel........................................................ 3-7
Tires.............................................................5-74
Aluminum or Chrome-Plated Wheels,
Cleaning.................................................5-89
Cleaning....................................................5-89
Dual Tire Operation.....................................5-76
If a Tire Goes Flat.......................................5-82
Inflation - Tire Pressure................................5-75
Tightening the Wheel Nuts............................5-77
Wheel Alignment and Tire Balance.................5-77
Wheel Loading............................................5-75
Wheel Replacement.....................................5-81
When It Is Time for New Tires......................5-76
Tow Hooks.....................................................4-33
12