Page 329 of 384

Scheduled Maintenance
The services shown in this schedule up to 100,000 miles
(166 000 km) should be repeated after 100,000 miles
(166 000 km) at the same intervals for the life of
this vehicle. The services shown after 100,000 miles
(166 000 km) should be repeated at the same miles (km)
after those intervals for the life of this vehicle.
Gasoline engine vehicles and some DURAMAX
®diesel
and Isuzu diesel engine vehicles have a computer
that lets you know when to change the engine oil. This
is not based on mileage, but on engine operation and
engine temperature. When the computer has calculated
that the oil needs changing, the Engine Oil Life System
will indicate that a change is necessary. SeeEngine Oil
Life System (Gasoline Engine) on page 5-36orEngine
Oil Life System (DURAMAX
®/Isuzu Diesel Engines) on
page 5-37orEngine Oil Life System (Caterpillar®Diesel
Engine) on page 5-39.
The “Footnotes” at the end of this Maintenance
Schedule further explain maintenance services.
SeeService Publications Ordering Information on
page 7-10.
100 Miles (160 km)
❑Wheel stud nut service.(36)
1,000 Miles (1 600 km)
❑Wheel stud nut service.(36)
❑Rear axle air shift motor service.(10)
7,500 Miles (12 000 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)
❑Spring-to-axle U-bolts and shackle bolts service.(15)
❑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).
6-5
Page 344 of 384

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.
❑Isuzu Diesel Only: Diesel Particulate Filter (DPF)
service (or every 4,500 hours, whichever occurs
first). Then every 150,000 miles (240 000 km),
or every 4,500 hours, whichever occurs first.(7)
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
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, 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)= Check for filter ash, sensor adjustment, and sensor
hose restriction. Clean as needed. This service can be
complex; you should have your dealer/retailer perform
this service.
(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.
6-20
Page 347 of 384

(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. SeePart C:
Recommended Fluids and Lubricants on page 6-31.
•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 5-81andPart C: Recommended Fluids
and Lubricants on page 6-31.
(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 7-10.
(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/retailer perform this service. SeePart C:
Recommended Fluids and Lubricants on page 6-31for
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.
6-23
Page 355 of 384

Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number, or specification can be obtained from your
dealer/retailer.
Usage Fluid/Lubricant
Engine Oil
(Gasoline
Engine)Engine oil which meets
GM Standard GM6094M and
displays the American Petroleum
Institute (API) Certified for Gasoline
Engines starburst symbol. To
determine the proper viscosity for
your vehicle’s engine, see “Engine
Oil” in the Index.
Engine Oil
(DURAMAX
®/
Isuzu Diesel
Engines)Engine oils with the letters CJ-4 are
required for your vehicle. The CJ-4
designation can appear either alone
or in combination with other
American Petroleum Institute (API)
designations, such as API CJ-4/SL.
These letters show API levels of
quality. To determine the preferred
viscosity for your vehicle’s diesel
engine, see “Engine Oil” in the Index.
Engine Oil
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine oil
recommendations.
Usage Fluid/Lubricant
Engine Coolant
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine
coolant recommendations.
Engine Coolant
(Gasoline
Engine &
DURAMAX
®/
Isuzu Diesel
Engines)50/50 mixture of clean, drinkable
water and use only DEX-COOL
®
Coolant. SeeEngine Coolant
(Caterpillar®Diesel Engines) on
page 5-44orEngine Coolant
(Gas and DURAMAX
®/Isuzu 7.8L
L6 Engines) on page 5-44.
Hydraulic Brake
SystemDelco
®Supreme 11 Brake Fluid or
equivalent DOT-3 brake fluid.
Windshield
Washer SolventOptikleen
®Washer Solvent.
Clutch Bearing
LubricantClutch Bearing Lubricant
(GM Part No. 12378484 or
equivalent NLGI #3 consistency).
Exhaust Brake
Ball Joint Cap
LubricantHigh-Temperature Grease
(GM Part No. U.S. 1051344, in
Canada 903037) or NLGI #3
consistency.
Power Steering
SystemDEXRON
®-VI Automatic
Transmission Fluid.
Manual
TransmissionSynthetic Manual Transmission Fluid
(GM Part No. U.S. 88861952, in
Canada 88861953).
6-31
Page 357 of 384
Part D: Maintenance Record
After the scheduled services are performed, record the date, odometer reading and who performed the service, and
any additional information from “Owner Checks and Services” on the following record pages. Also, you should
retain all maintenance receipts.
DateMiles/km Or
HoursServiced By Maintenance Record
6-33
Page 358 of 384
DateMiles/km Or
HoursServiced By Maintenance Record
6-34
Page 359 of 384
DateMiles/km Or
HoursServiced By Maintenance Record
6-35
Page 360 of 384
DateMiles/km Or
HoursServiced By Maintenance Record
6-36