
Wheel Replacement
Replace any wheel that is bent, cracked or badly rusted
or corroded. If wheel nuts keep coming loose, replace
the wheel. If the wheel leaks air, replace it.
Your dealer will know the kind of wheel you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted
the same way as the one it replaces.
If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM
original equipment parts. This way, you will be sure to
have the right wheel, wheel bolts and wheel nuts
for your vehicle.
{CAUTION:
A leaking wheel could fail without warning.
A wheel designed for tubeless tires could be
leaking because it is damaged. Don’t use
an inner tube or some other thing to try to
stop the leaking. Get a new wheel or the
proper type.
{CAUTION:
Without the correct wheel, you may not be able
to stop properly, and you could have other
problems like a tire air-out. You could have a
collision. If you don’t go to your dealer to get a
new wheel, be sure you get the correct one.
Each new wheel should match the original
wheel in load-carrying capacity, in ation
pressure capacity, diameter, width, offset and
mounting con guration.
Using wheels and tires with higher load-carrying limits
than the original wheels and tires doesn’t change
the GAWR or the GVWR of your vehicle. See “Loading
Your Vehicle” for more information.
Notice:The wrong wheel can cause trouble in
bearing life, brake cooling, speedometer/odometer
calibration, headlamp aim, bumper height, vehicle
ground clearance, stopping distance and tire
clearance to the body and chassis. You could also
have other problems like a tire air-out.
5-74

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
“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)
❑Inspect door hinge pins and bushings and replace as
necessary.
❑Cooling system service. Clean the cooling system filter
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.
❑Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever hubs
are removed).(23) (46)❑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)
❑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)
6-7

45,000 Miles (72 000 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)
❑Gasoline Engine: Inspect engine air cleaner filter if you
are driving in dusty conditions and replace filter if
necessary. Diesel Engine: Inspect engine air cleaner
filter change indicator. If necessary, replace the filter. If
vehicle is driven in dusty/dirty conditions, inspect filter
change indicator at every engine oil change. See
Engine Air Cleaner/Filter on page 5-30for more
information.† (3)
❑DURAMAX™ Diesel Only: Replace fuel filter.
❑Chassis lubrication service (or every 6 months,
whichever occurs first).(12)
❑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.
❑Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever hubs
are removed.)(23) (46)❑Inspect door hinge pins and bushings and replace as
necessary.
❑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)
❑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)
6-10

❑C600, C700 and C800 Gasoline Engines Only:
Engine drive belts service (or every 12 months,
whichever occurs first).(18)
❑Thermostatically controlled engine cooling fan
service.(4) (20)
❑Shields and underhood insulation service.(4) (5) (21)
❑Air compressor dry element pleated paper air
strainer service (or every 2 months or every
800 hours, whichever occurs first).
67,500 Miles (108 000 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)
❑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.
❑Wheel bearing (grease type) service (or every 24
months, whichever occurs first, and whenever hubs
are removed).(23) (46)❑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)
❑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) †
6-13

❑Gasoline Engine: Replace engine air cleaner filter.
Diesel Engine: Inspect engine air cleaner filter
change indicator. If necessary, replace the filter. If
vehicle is driven in dusty/dirty conditions, inspect filter
change indicator at every engine oil change. See
Engine Air Cleaner/Filter on page 5-30for more
information.† (3)
❑DURAMAX™ Diesel Only: Replace fuel filter.
❑Chassis lubrication service (or every 6 months,
whichever occurs first).(12)
❑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.
❑Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever
hubs are removed).(23) (46)
❑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)❑Inspect door hinge pins and bushings and replace as
necessary.
❑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)
❑C600, C700 and C800 Gasoline Engines Only:
Engine drive belts service (or every 12 months,
whichever occurs first).(18)
6-16

(14)= 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.
(15)= Adjust tire pressures as indicated on the GVW
Rating label for optimum tire life. SeeTires on page 5-68
for further details. Check tires for excessive or
abnormal wear or damage. Also check for damaged
wheels. Replace wheels and/or tires as needed.
(16)= 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.
(17)= 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.(18)= Check all gasoline engine drive belts for cracks,
fraying and wear. Replace as needed.
(20)= 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.
(21)= Check shields and underhood insulation for
damage or looseness. Adjust or replace as needed.
23)= Wheel bearing service:
•Grease type – Clean, inspect and lubricate with the
proper wheel bearing grease at designated intervals
or when hubs are removed. SeePart C:
Recommended Fluids and Lubricants on page 6-29.
•Oil-filled type – Some wheel bearings are lubricated
by rear axle lubricant. When you have oil-filled
hubs, use lubricant identical to that used in your rear
axle. Lubricant change intervals are the same for
front and rear axles. However, you must maintain oil
level at the OIL LEVEL mark between change
intervals. SeePart C: Recommended Fluids and
Lubricants on page 6-29.
6-21

Part B: Owner Checks and Services
Listed in this part are owner checks and services
which should be performed at the intervals specified to
help ensure the safety, dependability and emission
control performance of your vehicle.
For your safety and that of others, any of the
safety-related components that may have been
damaged in an accident should be checked and any
needed repairs made before operating the vehicle.
At the minimum, these routine checks should be made
every 6 months or 6,000 miles (10 000 km), whichever
occurs first. Whenever repairs are needed, have
them completed before operating the vehicle.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuel ll.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. See “Engine Oil” in the Index for further
details.
Engine Coolant Level Check
Check the engine coolant level and add DEX-COOL®
coolant mixture if necessary. See “Engine Coolant”
in the Index for further details.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the windshield
washer tank and add the proper fluid if necessary.
SeeCleaning the Outside of Your Vehicle on page 5-80
for further details.
Tire In ation Check
Check tire inflation cold. Make sure tires are inflated to
the pressures specified on the GVW Rating label.
SeeLoading Your Vehicle on page 4-33andTires on
page 5-68for further details.
6-24

Starter Switch Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular
brakes. See “Parking Brake” if necessary.
Do not use the accelerator pedal, and be ready to
turn off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only
in PARK (P), if equipped, or NEUTRAL (N). If
the starter works in any other position, your vehicle
needs service.
Automatic Transmission Shift Indicator
Check
Check that the indicator points to the gear chosen.
Steering Check
Be alert for any changes in steering action, abnormal
front tire wear or steering wheel position. An inspection
or service is needed when the steering wheel is
harder to turn or has too much free play, or if there are
strange sounds when turning or parking.
Brake System Check
Be alert to illumination of the low air warning lamp or for
the tone alarm, or changes in braking action, such as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Make sure air
brake system reservoirs are drained daily with full
system air pressure, and check system for leaks. Any of
these conditions could indicate the need for brake
system inspection and/or service.
Engine Cooling System Service
Inspect the hoses and have them replaced if they are
cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the
outside of the radiator and air conditioning condenser.
To help ensure proper operation, a pressure test of
the cooling system and pressure cap is recommended
at least once a year.
6-26