❑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.
❑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)
380
(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.
386
(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.
(14)= Adjust tire pressures as indicated on the
Certification or Tire Information label for optimum
tire life. SeeTires on page 321for further
details. Check tires for excessive or abnormal
wear or damage. Also check for damaged wheels.
Replace wheels and/or tires as needed.
(15)= Check spring-to-axle U-bolts and shackle
bolts for proper torque. See the service manual for
torque sequence and specifications. When parts
are replaced, the torque must be checked and
adjusted more often during the first 6,000 miles
(10 000 km). Check torque at 500 miles (800 km)
and 2,000 miles (3 000 km) after first use of parts.
(16)= Check complete exhaust system and
cab areas near the exhaust system for broken,
damaged, missing, or out-of-position parts.
Also inspect for open seams, holes, loose
connections, or other conditions which could let
exhaust fumes seep into the driver compartment.Needed repairs should be made at once. To help
maintain system integrity, replace exhaust
pipes whenever a new muffler is put on.
(17)= Check all gasoline engine drive belts for
cracks, fraying, and wear. Replace as needed.
(18)= Adjust valve lash. Incorrect valve clearance
will result in increased engine noise and reduced
engine output.
(19)= With the engine off and below normal
operating temperature, check to see that
the thermostatically controlled engine cooling fan
can be rotated by hand on viscous-operated
drives. Replace as needed.
(20)= Check shields and underhood insulation
for damage or looseness. Adjust or replace
as needed.
(21)= Inspect parking brake drum and linings for
wear or cracks and check linkage and adjustment.
387
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, CA1-163-005
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, the service bulletin reference number
can be obtained by contacting your General
Motors dealer or by calling 1-800-GM-DRIVE
(1-800-463-7483). This reference number is
needed to order the service bulletin
from Helm, Inc.
RETAIL SELL PRICE: $6.00 US +
Processing Fee
415
A
Accessory Power Outlet(s).......................... 156
Adding a Snow Plow or Similar
Equipment................................................ 240
Adding Equipment to Your Airbag-Equipped
Vehicle....................................................... 81
Additives, Fuel............................................ 252
Add-On Electrical Equipment....................... 340
Air Cleaner/Filter, Engine............................. 280
Air Conditioning........................................... 157
Air Conditioning System.............................. 320
Air Pressure Gage...................................... 183
Air Shift Control........................................... 114
Air Suspension............................................ 129
Air Suspension Seats.................................... 13
Airbag
Off Light.................................................. 166
Readiness Light....................................... 165
Airbag Sensing and Diagnostic
Module (SDM).......................................... 409
Airbag System............................................... 68
Adding Equipment to Your
Airbag-Equipped Vehicle......................... 81
Airbag Off Switch....................................... 76
How Does an Airbag Restrain?.................. 73
Servicing Your Airbag-Equipped Vehicle..... 80Airbag System (cont.)
What Makes an Airbag Inflate?.................. 73
What Will You See After an Airbag
Inflates?................................................. 74
When Should an Airbag Inflate?................. 72
Where Are the Airbags?............................. 70
AM-FM Radio.............................................. 186
Antenna, Fixed Mast................................... 204
Anti-Lock Brake System (ABS).................... 212
Anti-Lock Brake, System Warning Light....... 172
Anti-Lock Brakes, Trailer System
Warning Light........................................... 172
Appearance Care
Aluminum or Chrome-Plated Wheels........ 337
Care of Safety Belts................................ 334
Chemical Paint Spotting........................... 338
Cleaning Exterior Lamps/Lenses.............. 335
Cleaning the Inside of Your Vehicle.......... 331
Fabric/Carpet........................................... 333
Finish Care.............................................. 335
Finish Damage......................................... 338
Instrument Panel, Vinyl, and Other
Plastic Surfaces.................................... 334
Sheet Metal Damage............................... 337
Tires........................................................ 337
Underbody Maintenance........................... 338
Vehicle Care/Appearance Materials.......... 339
417
Seats
Air Suspension Seats................................. 13
Bucket Seats............................................... 9
Rear Seat Operation.................................. 20
Split Bench Seat........................................ 13
Securing a Child Restraint
Center Rear Seat Position (Crew Cab) or
Center Front Position.............................. 60
Rear Outside Seat Position........................ 58
Right Front Seat Position........................... 63
Service........................................................ 248
California Proposition 65 Warning............. 248
Doing Your Own Work............................. 249
Engine Fan Breakage.............................. 250
Engine Soon Light................................... 174
Publications Ordering Information............. 415
Transmission Warning Light..................... 168
Servicing Your Airbag-Equipped Vehicle......... 80
Setting the Time.......................................... 185
Sheet Metal Damage................................... 337
Shoulder Belt Height Adjuster........................ 35
Signals, Turn and Lane-Change.................. 144
Sliding Rear Windows................................... 94
Snow Plow.................................................. 240
Specifications, Capacities............................ 347
Speedometer............................................... 163Split Bench Seat........................................... 13
Starting Your Diesel Engine ......................... 100
Starting Your Gasoline Engine....................... 97
Steering...................................................... 217
Steering Wheel, Tilt Wheel.......................... 142
Storage Areas............................................. 135
Center Console Storage Area................... 135
Stuck in Sand, Mud, Ice, or Snow............... 236
Sun Visors.................................................... 95
Suspension, Air........................................... 129
Switchbanks, Instrument Panel.................... 154
T
Tachometer................................................. 163
Theft-Deterrent, Radio................................. 201
Tilt Wheel.................................................... 142
Tires........................................................... 321
Aluminum or Chrome-Plated Wheels,
Cleaning............................................... 337
Cleaning.................................................. 337
Dual Tire Operation.................................. 323
If a Tire Goes Flat................................... 330
Inflation - Tire Pressure............................ 322
Tightening the Wheel Nuts....................... 325
Wheel Alignment and Tire Balance........... 324
428