❑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
❑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) †
❑Gasoline Engine: Air compressor remote
mounted air filter dry element pleated paper
air strainer service (or every 6 months or
every 1800 hours, whichever occurs first).
96,000 Miles (152 000 km)
❑Isuzu 6H 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)
❑Isuzu 6H 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
®/Isuzu 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).
381
❑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)
❑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.
382
200,000 Miles (320 000 km)
❑Rear axle service — Eaton®, Rockwell®,
Spicer®axles (or every 12 months,
whichever occurs first).(30)
❑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)
❑Rear axle service — Eaton®, Rockwell®,
Spicer®axles (or every 12 months,
whichever occurs first).(30)
❑Remove, disassemble, clean, and inspect
the air brake air dryer (or every 3 years,
or 10,800 hours, whichever occurs first).
Replace desiccant.
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.
383
(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, front and rear axles,
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.
Remember to reset the Engine Oil Life System
whenever the oil is changed. For more information,
seeEngine Oil Life System (Gasoline Engine)
on page 276orEngine Oil Life System
(DURAMAX
®Diesel) on page 278orEngine
Oil Life System (Caterpillar®Diesel Engine)
on page 279.
384
(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
(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. See
Part C: Recommended Fluids and Lubricants
on page 397for 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. See
Part C: Recommended Fluids and
Lubricants on page 397.
(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.
•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.
389