
75,000 Miles (120 000 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)
❑6.6L DURAMAX
®Diesel Without Engine Oil Life
System Only: Change engine oil and filter (or every
12 months, or every 750 hours of engine operation,
whichever occurs first).(2)
❑6.6L DURAMAX
®Diesel With Engine Oil Life System
Only: Check oil life system. If engine oil and filter are
changed, reset system. See “Engine Oil (DURAMAX
®
Diesel)” in the Index.(2) (9)
❑Chassis lubrication service (or every 6 months,
whichever occurs first).(11)
❑Check fluid levels (or every 3 months, whichever
occurs first).(1) (5)
❑Gasoline Engine: Inspect engine air cleaner filter. If
necessary, replace the filter. If vehicle is driven in
dusty/dirty conditions, inspect filter at every engine oil
change. SeeEngine Air Cleaner/Filter on page 5-33
for more information.
❑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. SeeEngine Air
Cleaner/Filter on page 5-33for more information.❑DURAMAX
®Diesel Only: Replace fuel filter (or every
750 hours of engine operation, whichever occurs first).
❑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)
❑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)
❑Fuel tank, fuel cap and fuel lines service (or every
72 months, whichever occurs first).(2) (26) †
6-16

90,000 Miles (144 000 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)
❑6.6L DURAMAX
®Diesel Without Engine Oil Life
System Only: Change engine oil and filter (or every
12 months, or every 750 hours of engine operation,
whichever occurs first).(2)
❑6.6L DURAMAX
®Diesel With Engine Oil Life System
Only: Check oil life system. If engine oil and filter are
changed, reset system. See “Engine Oil (DURAMAX
®
Diesel)” in the Index.(2) (9)
❑Check fluid levels (or every 3 months, whichever
occurs first).(1) (5)
❑Gasoline Engine: Replace engine air cleaner filter.
SeeEngine Air Cleaner/Filter on page 5-33for more
information.
❑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. SeeEngine Air
Cleaner/Filter on page 5-33for more information.
❑DURAMAX
®Diesel Only: Replace fuel filter (or every
750 hours of engine operation, whichever occurs first).
❑Chassis lubrication service (or every 6 months,
whichever occurs first).(11)❑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).(22) (36)
❑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.
❑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)
6-18

❑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).
❑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.
6-20

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)
❑Rear axle service — Eaton
®, Rockwell®, Spicer®
axles (or every 36 months, whichever occurs
first).(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.
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 only to vehicles sold in the United States.
(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.
6-21

(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.
(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.
(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.
6-23

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.
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. On manual transmission vehicles,
the starter should work only when the clutch pedal is
all the way down.
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.
6-29

Canadian Roadside Assistance
In Canada, Medium Duty trucks are not eligible for
Roadside Assistance services. However,
owners/operators who contact Roadside Assistance by
calling 1-800-268-6800 may have a tow arranged
for them at the owner/operator expense.
If a Medium Duty truck is towed to a General Motors
dealership and the towing was necessary due to failure
of a warranted part, the dealer will accept the towing
charges and submit them as part of the warranty claim.
Vehicle Data Collection and Event
Data Recorders
Your vehicle, like other modern motor vehicles, has a
number of sophisticated computer systems that monitor
and control several aspects of the vehicle’s performance.
Your vehicle uses on-board vehicle computers to monitor
emission control components to optimize fuel economy,
to monitor conditions for airbag deployment and, if so
equipped, to provide anti-lock braking and to help the
driver control the vehicle in difficult driving situations.
Some information may be stored during regular
operations to facilitate repair of detected malfunctions;
other information is stored only in a crash event by
computer systems, such as those commonly called event
data recorders (EDR).In a crash event, computer systems, such as the Airbag
Sensing and Diagnostic Module (SDM) in your vehicle
may record information about the condition of the vehicle
and how it was operated, such as data related to
engine speed, brake application, throttle position, vehicle
speed, safety belt usage, airbag readiness, airbag
performance, and the severity of a collision. If your
vehicle is equipped with Quadrasteer, steering
performance, including yaw rate, steering wheel angle,
and lateral acceleration, is also recorded. This
information has been used to improve vehicle crash
performance and may be used to improve crash
performance of future vehicles and driving safety. Unlike
the data recorders on many airplanes, these on-board
systems do not record sounds, such as conversation of
vehicle occupants.
To read this information, special equipment is needed
and access to the vehicle or the device that stores
the data is required. GM will not access information
about a crash event or share it with others other than:
•with the consent of the vehicle owner or, if the
vehicle is leased, with the consent of the lessee,
•in response to an official request of police or similar
government office,
•as part of GM’s defense of litigation through the
discovery process, or
•as required by law.
7-6

F
Filter
Engine Air Cleaner......................................5-33
Filter Minder Gage..........................................3-43
Finish Damage...............................................5-85
Fixed Mast Antenna........................................3-59
Flat Tire........................................................5-78
Fluid
Automatic Transmission................................5-34
Manual Transmission....................................5-35
Power Steering...........................................5-45
Windshield Washer......................................5-46
Four-Wheel Drive....................................2-33, 5-62
Front Axle......................................................5-63
Front Wheel Bearings with Oil-Filled Hubs..........5-69
Fuel............................................................... 5-6
Additives...................................................... 5-6
Diesel Engine Fuel........................................ 5-7
Filling a Portable Fuel Container....................5-19
Filling Your Tank..........................................5-18
Filter..........................................................5-66
Filter Replacement.......................................5-16Fuel (cont.)
Fuels in Foreign Countries............................5-17
Gage.........................................................3-42
Gasoline Octane........................................... 5-6
Gasoline Specifications.................................. 5-6
Primary Filter and Water Separator................5-67
Running Out of Fuel....................................5-15
Secondary Filter and Water
Separator/Heater......................................5-68
Very Cold Weather Operation........................5-10
Water in Fuel..............................................5-10
Water in Warning Light.................................3-43
What Fuel to Use.......................................... 5-8
Fuses
Fuses and Circuit Breakers...........................5-89
Instrument Panel Fuse Block.........................5-89
Underhood Fuse Block.................................5-92
Windshield Wiper.........................................5-88
6