Page 327 of 366

❑Thermostatically controlled engine cooling fan
service.(4) (20)
❑Shields and underhood insulation service.(4) (5) (21)
❑Rear axle air shift motor service.(11)
❑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) †
97,500 Miles (156 000 km)
❑Gasoline Engine Only: Check Oil Life System. If
engine oil and filter are changed, reset system.
See “Engine Oil (Gasoline Engine)” 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)
❑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)
❑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)
100,000 Miles (160 000 km)
❑DURAMAX™ Diesel Only: Change engine oil
and filter (or every 12 months, whichever occurs
first).(2) (3)
❑Diesel Only: Inspect engine drive belt; replace as
necessary.
❑Gasoline Engine Only (Vehicles with GVW of
16,000 lbs. or less): Spark plug service.(3) (28)
❑Change power steering fluid (or every 36 months,
whichever occurs first).(13)
6-17
Page 329 of 366

300,000 Miles (480 000 km)
❑Remove, disassemble, clean and inspect the air
brake air dryer (or every 3 years, or 10,800 hours,
whichever occurs first). Replace desiccant on
Bendix-Westinghouse units.
Footnotes
† = The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle’s useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
(1)= If your vehicle has an Allison automatic
transmission, your GM owner’s manual is supplemented
by an Allison Transmission
®Operator’s Manual.
Always refer to these manuals for related maintenance
services.
(2)= Refer to the Caterpillar
®Diesel Engine Operation
and Maintenance Manual for oil recommendations
and change intervals.
(3)= An Emission Control Service.
(4)= A Noise Emission Control Device.
(5)= Applies only to vehicles sold in the United States.(6)= Check fluid level in brake master cylinder, power
steering pump, axle, transmission and hydraulic
spring parking brake pump (if equipped). A low fluid
level in the brake master cylinder can indicate
worn brake linings and should be checked accordingly.
(7)= Inspect brake lines and hoses for proper
hook-up, binding, leaks, cracks, chafing, etc. Inspect
disc brake pads for wear and rotors for surface
condition. Inspect caliper assemblies. Check brake
pedal for excessive free play or travel (or every
6 months, whichever occurs first) and have serviced if
needed. Check brakes more often if driving habits
and conditions result in frequent braking.
(8)= Inspect parking brake drum and linings for wear or
cracks and check linkage and adjustment.
(9)= This vehicle has the GM Oil Life System. This
system will show you when to change the engine oil and
filter – usually between 3,000 miles (5 000 km) and
7,500 miles (12 000 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 000 km) or 12 months
without an oil and filter change.
Remember to reset the Oil Life System whenever the oil
is changed. For more information, seeChange Engine
Oil Light on page 3-39.
6-19
Page 363 of 366

Safety Belts (cont.)
Safety Belt Extender....................................1-26
Safety Belt Use During Pregnancy.................1-21
Safety Belts Are for Everyone......................... 1-8
Safety Warnings and Symbols.............................. iii
Scheduled Maintenance..................................... 6-5
Scheduled Maintenance Supplements.................. 6-4
Seat Adjuster Check........................................6-27
Seatback Adjustment......................................... 1-3
Seats
Air Suspension Seats.................................... 1-6
Manual........................................................ 1-2
Rear Seat Operation...................................... 1-7
Reclining Seatbacks...................................... 1-4
Split Bench Seat........................................... 1-6
Securing a Child Restraint
Center Rear Seat Position (Crew Cab) or
Center Front Position................................1-41
Rear Outside Seat Position...........................1-39
Right Front Seat Position..............................1-43
Service........................................................... 5-3
Doing Your Own Work................................... 5-4
Engine Soon Light.......................................3-37
Publications Ordering Information..................... 7-7
Transmission Warning Light..........................3-31
Two Safety Cautions about Engine Fan
Breakage.................................................. 5-5Service Bulletins............................................... 7-8
Service Engine Soon Light...............................3-37
Service Manuals............................................... 7-7
Servicing Your Air Bag-Equipped Vehicle............1-60
Setting Preset Stations....................3-47, 3-49, 3-54
Setting the Time.............................................3-45
Setting the Tone (Bass/Treble)..........3-47, 3-49, 3-54
Sheet Metal Damage.......................................5-82
Shoulder Belt Height Adjuster...........................1-15
Skidding........................................................4-16
Sliding Rear Windows.....................................2-10
Some Other Rainy Weather Tips.......................4-20
Special Fabric Cleaning Problems.....................5-78
Specifications, Capacities.................................5-93
Speedometer..................................................3-25
Split Bench Seat.............................................. 1-6
Starter Motor Operation...................................2-13
Starter Switch Check.......................................6-26
Starting Your Diesel Engine..............................2-14
Starting Your DURAMAX™ Diesel Engine...........2-19
Starting Your Engine...............................2-13, 2-19
Starting Your Gasoline Engine..........................2-12
Steering........................................................4-12
Steering Check...............................................6-26
Steering in Emergencies..................................4-13
Steering Tips..................................................4-12
Stopping the Diesel Engine..............................2-15
Stopping the Gasoline Engine...........................2-14
13