❑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
96,000 Miles (152 000 km)
❑7.8L DURAMAX®Diesel Without Engine Oil Life
System Only: Change engine oil and filter
(or every 12 months, or every 600 hours of engine
operation, whichever occurs first).(2)
❑7.8L DURAMAX
®Diesel With Engine Oil Life System
Only: Check oil life system (or every 12 months, or
every 600 hours of engine operation, whichever
occurs first). If engine oil and filter are changed, reset
system. See “Engine Oil (DURAMAX
®Diesel)” in
the Index.(2) (7)
❑Lubricate U-joints (or every 6 months, whichever
occurs first).
97,500 Miles (156 000 km)
❑Gasoline Engine Only: Check engine oil life system.
If engine oil and filter are changed, reset system.
See “Engine Oil (Gasoline Engine)” in the
Index.(2) (8)
❑Check fluid levels (or every 3 months, whichever
occurs first).(1) (5)
❑Chassis lubrication service (or every 6 months,
whichever occurs first).(11)
❑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)100,000 Miles (160 000 km)
❑Diesel Only: Inspect engine drive belt; replace as
necessary.
❑Gasoline Engine Only (Vehicles with GVW of
16,000 lbs or less): Spark plug service.(2) (25)
❑Change power steering fluid (or every 36 months,
whichever occurs first).(12)
❑Replace power steering reservoir filter element (or
every 24 months, whichever occurs first).
❑Wheel bearing (oil type) service (and whenever hubs
are removed).(22) (36)
6-20
❑Except four-wheel drive: Front axle service.(31)
❑Four-wheel drive only: Front axle service.(30)
❑Four-wheel drive only: Transfer case service.(30)
❑Rear axle service — Eaton
®, Rockwell®, Spicer®
axles (or every 12 months, whichever occurs
first).(30)
❑Exhaust brake service, if equipped. Check for
excessive spindle free play and smooth operation.
Lubricate ball joint cap.
❑Inspect air compressor discharge port (or every
6 months or every 1,800 hours, whichever
occurs first).
❑Manual transmission (ZF 6-speed only) fluid
replacement (or every 48 months, whichever
occurs first).
❑Trailer brake hand control valve service (or every
12 months, or every 3,600 hours, whichever
occurs first).(35)
120,000 Miles (192 000 km)
❑C600, C700, and C800 Gasoline Engines
Only: Replace engine drive belts.
❑C400 and C500 Gasoline Engines Only: Engine drive
belts service (or every 12 months, whichever occurs
first).(17)
150,000 Miles (240 000 km)
❑Cooling system service (or every 60 months since
last service, whichever occurs first).(2) (29)
❑Diesel Engine Only: Inspect engine drive belt;
replace as necessary.
200,000 Miles (320 000 km)
❑Remove, disassemble, clean, and inspect the air
brake trailer supply valve (or every 2 years, or
every 7,200 hours, whichever occurs first).
❑Diesel Engine Only: Inspect engine drive belt;
replace as necessary.
250,000 Miles (400 000 km)
❑Four-wheel drive only: Front axle service.(30)
❑Four-wheel drive only: Transfer case service.(30)
❑Manual transmission (except ZF 6-speed) fluid
replacement (or every 60 months, whichever
occurs first).
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.
6-21
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 Transmission
®, your
GM owner manual is supplemented by an Allison
Transmission
®Operator’s Manual. Always refer to these
manuals for related maintenance services.
(2)= An Emission Control Service.
(3)= A Noise Emission Control Device.
(4)= Applies to vehicles sold in the United States and is
recommended for vehicles sold in Canada.(5)= 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.
(6)= 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.
(7)= This vehicle has the Engine 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
12,000 miles (20 000 km) since your last oil change.
Under severe conditions, the indicator may come
on before 3,000 miles (5 000 km). Never drive your
7.8L diesel engine vehicle more than 12,000 miles
(20 000 km), or 12 months, or 600 engine hours, without
an oil and filter change.
6-22
Remember to reset the Engine Oil Life System
whenever the oil is changed. For more information, see
Engine Oil Life System (Gasoline Engine) on page 5-31
orEngine Oil Life System (DURAMAX
®Diesel) on
page 5-33orEngine Oil Life System (Caterpillar®Diesel
Engine) on page 5-34.
(8)= This vehicle has the Engine 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
gasoline engine vehicle more than 7,500 miles
(12 000 km) or 12 months without an oil and filter
change.
Remember to reset the Engine Oil Life System
whenever the oil is changed. For more information, see
Engine Oil Life System (Gasoline Engine) on page 5-31
orEngine Oil Life System (DURAMAX
®Diesel) on
page 5-33orEngine Oil Life System (Caterpillar®Diesel
Engine) on page 5-34.(9)= This vehicle has the Engine 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
15,000 miles (24 000 km) since your last oil change.
Under severe conditions, the indicator may come
on before 3,000 miles (5 000 km). Never drive your
6.6L diesel engine vehicle more than 15,000 miles
(24 000 km), or 12 months, or 750 engine hours, without
an oil and filter change.
Remember to reset the Engine Oil Life System
whenever the oil is changed. For more information, see
Engine Oil Life System (Gasoline Engine) on page 5-31
orEngine Oil Life System (DURAMAX
®Diesel) on
page 5-33orEngine Oil Life System (Caterpillar®Diesel
Engine) on page 5-34.
(10)= Inspect rear axle air shift motor for fluid leaks.
Remove plug to check fluid level. Inspect air lines
and hoses for proper hook-up, binding, leaks, etc.
Inspect at 1,000 miles (1 600 km) and 22,500 miles
(36 000 km) and then every 22,500 miles (36 000 km)
thereafter.
6-23
(14)= Adjust tire pressures as indicated on the Gross
Vehicle Weight (GVW) Rating label for optimum tire life.
SeeTires on page 5-74for 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.
(22)= Wheel bearing service:
•Grease type — Clean, inspect, and lubricate with
the proper wheel bearing grease at designated
intervals or when hubs are removed. See
Part C: Recommended Fluids and Lubricants on
page 6-33.
•Oil-filled type — Some wheel bearings are
lubricated by axle lubricant. When you have oil-filled
hubs, use lubricant identical to that used in the
axle. Lubricant change intervals are the same for
front and rear axles. However, you must maintain
the proper oil level between change intervals.
SeeFront Wheel Bearings with Oil-Filled Hubs on
page 5-73andPart C: Recommended Fluids
and Lubricants on page 6-33.
6-25
(23)= Check the air intake system installation to see
that gaskets are seated properly and all hose
connections, fasteners, and other components are tight.
Tighten connections and fasteners or replace parts
as required.
(24)= Evaporative Control System Service, if
equipped: Check all fuel and vapor lines and hoses
for proper connections and correct routing (or every
24 months, whichever occurs first). Replace parts
as needed.
(25)= Replace spark plugs. Inspect wires for damage.
Check the wire boot and boot heat shield fit at spark
plugs and coil. Replace parts as needed.
(26)= Check the fuel tank, fuel cap and fuel lines for
damage which could cause leakage. Inspect fuel cap for
correct sealing ability and any indications of damage.
Check fuel cap gasket for even filler neck imprint.
Replace parts as needed.
(27)= Check Exhaust Gas Recirculation (EGR) system
as described in the service manual. SeeService
Publications Ordering Information on page 7-11.
(28)= Inspect Electronic Vacuum Regulator Valve
(EVRV) filter for excessive contamination or plugging.
If needed, clean filter with solution of soap and water, let
dry and install.(29)= Drain, flush, and refill cooling system. This
service can be complex; you should have your dealer
perform this service. SeePart C: Recommended Fluids
and Lubricants on page 6-33for what to use. Inspect
hoses. Clean radiator, condenser, pressure cap,
and neck. Pressure test cooling system and pressure
cap. For Caterpillar
®diesel engines, always refer to the
Caterpillar®Diesel Engine Operation & Maintenance
Manual for coolant recommendations and change
intervals.
(30)= Change the lubricant. SeePart C: Recommended
Fluids and Lubricants on page 6-33.
(31)= Front axle service: Re-pack upper kingpin roller
bearing.
(32)= Air brake service:
•Inspect brake lines and hoses for proper hook-up,
binding, leaks, cracks, chafing, etc. Inspect drum
brake linings for wear or cracks. Inspect other brake
parts at each wheel, including drums and wheel
speed sensor wiring. 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. Replace air
dryer cartridge only if excessive oil or moisture
is present. A small amount of oil in the system is
normal and should not be considered as a reason to
replace the cartridge.
6-26
•Test air lines for leaks; tighten as needed. Replace
compressor filter.
•Inspect air parking brake chamber for leaks and
damage. Inspect lines and hoses for leaks,
cracks, chafing, etc. Also check all attachments for
tightness, wear, or damage. Note: The spring
brake section of the rear brake diaphragms are
non-serviceable.
•Replace the air compressor filter element, mounted
on the air compressor. For remote air compressor
intake service, refer to engine air cleaner filter
replacement.
•Remove, disassemble, clean, and inspect the safety
valve, standard brake chambers, quick release
valves, quick release/double check valve
combinations, parking brake control valve, double
check valves, pressure protection valves, and
alcohol injector (if equipped).
•Remove, disassemble, and clean the application
valve; replace parts showing wear.
•Remove, disassemble, clean, and inspect the
spring brake control valve; replace rubber parts.(33)= Clean and lubricate air brake automatic slack
adjuster. Check pushrod travel and auto adjustment
operation. Have serviced if needed.
(34)= Air brake chamber service: Check operation,
mounting clamps, and air lines and check for leaks.
(35)= Trailer brake hand control valve service: Check
operation; lubricate cam and follower.
(36)= Tighten the wheel stud nuts to the specified
torque values at 100 miles (160 km). Thereafter, tighten
them 1,000 miles (1 600 km) after each time the
wheel is removed. SeeTightening the Wheel Nuts on
page 5-77.
(37)= Inspect and clean any accumulated dirt, gravel,
or other foreign objects from the valves and valve boots
as needed. Using light oil, lubricate brake pedal to
brake application valve linkage components. Check any
rubber boots for cracks, holes, or deterioration and
replace if necessary.
6-27