
Part GM Part Number ACDelco Part Number
Fuel Filter
6.6L V8 98017645 TP1298B
7.2L L6 — 1R-0751
2
Isuzu 6H 98026037 —
8.1L V8 (C4/C5 with NG6/NK1 or U-Haul) 15807649 —
8.1L V8 (C4/C5 with all other fuel tanks) 10376257 —
8.1L V8 (All C6/C7/C8) 10370247 —
Power Steering Fluid Filter 88892858 —
Secondary Fuel Filter
6.6L V8 — —
7.2L L6 (NWB/KUR) 25982639 S3229
3
Isuzu 6H (NWB) 15618921 S32023
Isuzu 6H (KUK) 88983117 TP1519
8.1L V8 (K28 and standard U-Haul) 25014476 TP1247
Spark Plugs
6.6L V8 — —
7.2L L6 — —
Isuzu 6H — —
8.1L V8 12578277 41-983
1Optional air filter (GM Part No. 88937548 AC Delco No. A2035C) for C6/C7/C8 Models. Fits inside standard size
filter (GM Part No. 88937525 AC Delco No. A2031C) listed previously.
2Caterpillar®part number.3Racor part number.
See the Allison Transmission Operator’s Manual in your vehicle for external filter part numbers and information.
5-109

❑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)
❑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)
❑DURAMAX Diesel Only: Diesel Particulate
Filter (DPF) service. Then every 100,000 miles
(160 000 km).(7) (38)
6-19

(4)= Applies to vehicles sold in the United States and is
recommended for vehicles sold in Canada.
(5)= Check fluidlevel 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.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 5-35
orEngine Oil Life System (DURAMAX/Isuzu Diesel
Engines) on page 5-36orEngine Oil Life System
(Caterpillar Diesel Engine) on page 5-38.
(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
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 5-35
orEngine Oil Life System (DURAMAX/Isuzu Diesel
Engines) on page 5-36orEngine Oil Life System
(Caterpillar Diesel Engine) on page 5-38.
(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.
6-21

(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.
6-22

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 5-47.
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).
Automatic
TransmissionSee the Allison Transmission
®
Operator’s Manual for correct
transmission fluid.
6-31

Engine (cont.)
Overheating................................................5-48
Overspeed Warning Light..............................3-40
Reduced Power Light...................................3-42
Shutdown Warning Light...............................3-40
Speed Limiter.............................................3-25
Starter Over-Crank Protection........................2-12
Starting Diesel............................................2-14
Starting the Gasoline...................................2-12
Entry Lighting.................................................3-17
Event Data Recorders.....................................7-12
Exhaust Brake Indicator Light...........................3-41
Exhaust Restrictor...........................................2-22
Extender, Safety Belt.......................................1-28
Exterior Lamps...............................................3-14
F
Filter
Engine Air Cleaner......................................5-38
Filter Minder Gage..........................................3-46
Finish Damage...............................................5-93
Fixed Mast Antenna........................................3-58
Flashers, Hazard Warning.................................. 3-6
Flat Tire........................................................5-85
Fluid
Automatic Transmission................................5-42
Power Steering...........................................5-49
Windshield Washer......................................5-50
Four-Wheel Drive....................................2-30, 5-68Front Axle......................................................5-69
Front Wheel Bearings with
Oil-Filled Hubs............................................5-75
Fuel............................................................... 5-6
Additives...................................................... 5-7
Change Filter Warning Light..........................3-45
Diesel Engine Fuel........................................ 5-8
Driving for Better Economy............................. 4-2
Filling a Portable Fuel Container....................5-22
Filling the Tank...........................................5-20
Filter..........................................................5-72
Filter Replacement.......................................5-18
Fuels in Foreign Countries............................5-19
Gage .........................................................3-44
Gasoline Octane........................................... 5-6
Gasoline Specifications.................................. 5-7
Primary Filter and Water Separator................5-73
Running Out of Fuel....................................5-17
Secondary Filter and Water
Separator/Heater......................................5-74
Very Cold Weather Operation........................5-11
Water in Fuel..............................................5-11
Water in Warning Light.................................3-45
What Fuel to Use.......................................... 5-8
Fuses
Fuses and Circuit Breakers...........................5-96
Instrument Panel Fuse Block.........................5-96
Underhood Fuse Block.................................5-99
Windshield Wiper.........................................5-95
5

Outside
Convex Mirrors............................................2-52
Heated Mirrors............................................2-52
Manual Mirrors............................................2-51
Power Mirrors.............................................2-51
Overspeed Warning Light.................................3-40
P
Paint, Damage...............................................5-93
Park Brake............................................2-38, 2-41
Parking.........................................................2-35
Brake Burnish Procedure..............................2-43
Over Things That Burn.................................2-44
Two-Speed Rear Axle..................................2-36
Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-26
PartC-Recommended Fluids and
Lubricants..................................................6-31
PartD-Maintenance Record...........................6-33
Passing.........................................................4-11
Perchlorate Materials Requirements,
California..................................................... 5-4
Power
Door Locks.................................................. 2-7
Electrical System.........................................5-96
Reduced Engine Light..................................3-42
Steering Fluid.............................................5-49
Windows...................................................... 2-9
Power Take-Off Light.......................................3-43Power Take-Off (PTO).....................................2-30
Privacy..........................................................7-11
Event Data Recorders..................................7-12
Navigation System.......................................7-13
OnStar.......................................................7-13
Radio Frequency Identification.......................7-13
R
Radio Frequency Identification (RFID),
Privacy......................................................7-13
Radio(s)........................................................3-49
Radios
Reception...................................................3-58
Setting the Clock.........................................3-48
Theft-Deterrent............................................3-57
Range Inhibit Warning Indicator........................3-31
Reading Lamps..............................................3-17
Rear Axle......................................................5-67
Differential Lock Control................................. 4-7
Shift Motor.................................................5-68
Rear Heating System......................................3-23
Rear Seat Operation.......................................1-10
Rearview Mirrors.............................................2-51
Reduced Engine Power Light............................3-42
Remote Keyless Entry (RKE) System.................. 2-3
Remote Keyless Entry (RKE) System,
Operation..................................................... 2-4
Replacement Parts, Maintenance.....................5-108
9