
To reset the change engine oil light:
1. Turn the ignition key to ON/RUN with the
engine off.
2. Fully press and release the accelerator pedal slowly
three times within 10 seconds.
If the change engine oil light flashes for
five seconds, the system is resetting.
3. Turn the key to OFF.
If the change engine oil light comes back on when the
vehicle is started, the engine oil life system has not
reset. Repeat the procedure.
What to Do with Used Oil
Used engine oil contains certain elements that can be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good
hand cleaner. Wash or properly dispose of clothing or
rags containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Recycle it by taking it to a
place that collects used oil.
Engine Oil Life System
(DURAMAX/Isuzu Diesel Engines)
When to Change Engine Oil
If the vehicle has the Engine Oil Life System, it has a
computer system that indicates when to change
the engine oil and filter. This is based on injection timing,
engine load, and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change is indicated can vary considerably.
For the oil life system to work properly, the system
must be reset every time the oil is changed.
When the system has calculated that oil life has been
diminished, it indicates that an oil change is necessary.
A change engine oil light comes on. SeeChange Engine
Oil Light on page 3-39. Change the oil as soon as
possible within the next 600 miles (1 000 km) or 30 hours
of engine operation, whichever occurs first. It is possible
that, if driving under the best conditions, the oil life system
might not indicate that an oil change is necessary for over
a year. However, the engine oil and filter must be
changed at least once a year and at this time the system
must be reset. Your dealer/retailer has trained service
people who will perform this work using genuine parts
and reset the system. It is also important to check the oil
regularly and keep it at the proper level.
5-36

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. 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.
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)
6-5

(14)= Adjust tire pressures as indicated on the
Certification or Tire Information label for optimum tire
life. SeeTires on page 5-76for 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, including DPF
pressure lines, 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. 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 5-75andPart 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.
6-23

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

Diesel Engine.................................................2-26
Engine Alarm and Automatic Shutdown...........2-18
Exhaust Restrictor.......................................2-22
Fuel............................................................ 5-8
High Idle System.........................................2-20
Starting......................................................2-14
Diesel Particulate Filter....................................2-46
Diesel Particulate Filter Warning Light................3-46
Differential Lock Control, Rear Axle..................... 4-7
Differential Lock Indicator Light.........................3-41
Doing Your Own Service Work........................... 5-5
Dome Lamps .................................................3-16
Door
Locks.......................................................... 2-6
Power Door Locks......................................... 2-7
Driving
At Night.....................................................4-13
Defensive..................................................... 4-2
Drunken....................................................... 4-3
Highway Hypnosis.......................................4-15
Hill and Mountain Roads..............................4-16
In Rain and on Wet Roads...........................4-14
Rocking Your Vehicle to Get it Out.................4-19
Tow Hooks.................................................4-20
Winter........................................................4-17
Driving for Better Fuel Economy......................... 4-2
Dual Tire Operation.........................................5-78E
EDR .............................................................7-11
Electrical System
Add-On Equipment......................................5-95
Fuses and Circuit Breakers...........................5-96
Fusible Links..............................................5-95
Headlamp Wiring.........................................5-95
Instrument Panel Fuse Block.........................5-96
Power Windows and Other Power Options......5-96
Underhood Fuse Block.................................5-99
Windshield Wiper Fuses...............................5-95
Engine
Air Cleaner/Filter.........................................5-38
Alarm and Automatic Shutdown.....................2-18
Change Engine Oil Light...............................3-39
Check and Service Engine Soon Lamp...........3-36
Checks Before Operating..............................2-23
Coolant......................................................5-47
Coolant Heater............................................2-25
Coolant Temperature Gage...........................3-34
Diesel Engine Exhaust Brake........................2-26
Drive Belt Routing......................................5-110
Exhaust.....................................................2-45
Exhaust Restrictor.......................................2-22
Fan Breakage............................................... 5-6
Fan Noise..................................................5-49
High Idle System.........................................2-20
Oil ....................................5-24, 5-27, 5-28, 5-32
Oil Life System...........................5-35, 5-36, 5-38
4

G
Gage
Air Pressure...............................................3-47
Check Gages Warning Light..........................3-43
Engine Coolant Temperature.........................3-34
Filter Minder...............................................3-46
Fuel..........................................................3-44
Hourmeter..................................................3-47
Oil Pressure...............................................3-38
Speedometer..............................................3-25
Tachometer.................................................3-25
Transmission Temperature.............................3-40
Voltmeter Gage...........................................3-30
Gasoline
Octane........................................................ 5-6
Specifications............................................... 5-7
Gasoline Engine, Starting.................................2-12
GM Mobility Reimbursement Program.................. 7-5
H
Hazard Warning Flashers................................... 3-6
Headlamp Wiring............................................5-95
Headlamps
Bulb Replacement.......................................5-71
Daytime Running Lamp................................3-15
Exterior Lamps............................................3-14
High/Low Beam Changer................................ 3-8
On Reminder..............................................3-14Heater...........................................................3-20
Engine Coolant...........................................2-25
High Idle System............................................2-20
Highbeam On Light.........................................3-42
Highway Hypnosis...........................................4-15
Hill and Mountain Roads..................................4-16
Hood
Checking Things Under................................5-22
Latches......................................................5-23
Horn ............................................................... 3-6
Hourmeter Gage.............................................3-47
How to Wear Safety Belts Properly...................1-16
I
Ignition Positions.............................................2-11
Infants and Young Children, Restraints...............1-32
Inflation - Tire Pressure...................................5-77
Instrument Panel
Brightness..................................................3-16
Cluster.......................................................3-24
Overview..................................................... 3-4
Switchbank.................................................3-18
J
Jump Starting.................................................5-62
6