Page 276 of 430

GM Goodwrench®oil of the recommended
viscosity grades meets all the requirements for
your vehicle.
Engine Oil Additives
Do not add anything to the oil. The recommended
oils with the API service symbol are all you will
need for good performance and engine protection.
When to Change Engine Oil (Vehicles
Without the Engine Oil Life System)
If you have the 6.6L V8 DURAMAX®Engine:
Change engine oil and filter every 15,000 miles
(24 000 km), or every 12 months, or every
750 hours of engine operation, whichever occurs
first. If you have the Isuzu 6H Engine: Change
engine oil and filter every 12,000 miles
(20 000 km), or every 12 months, or every
600 hours of engine operation, whichever occurs
first. SeeScheduled Maintenance on page 363.
Engine Oil Life System
(Gasoline Engine)
When to Change Engine Oil
Your vehicle has a computer system that lets you
know when to change the engine oil and filter.
This is based on engine revolutions and engine
temperature, and not on mileage. Based on driving
conditions, the mileage at which an oil change
will be indicated can vary considerably. For the oil
life system to work properly, you must reset the
system every time the oil is changed.
When the system has calculated that oil life has
been diminished, it will indicate that an oil change is
necessary. A change engine oil light will come on.
SeeChange Engine Oil Light on page 176. Change
your oil as soon as possible within the next
600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for
over a year. However, your engine oil and filter
must be changed at least once a year and at this
time the system must be reset. Your dealer has
GM-trained service people who will perform this
work using genuine GM parts and reset the system.
It is also important to check your oil regularly and
keep it at the proper level.
276
Page 362 of 430

Part A: Scheduled Maintenance
Services
In this part are scheduled maintenance services
which are to be performed at the mileage intervals
specified.
Using the Maintenance Schedule
We at General Motors want to help keep
your vehicle in good working condition. But we do
not know exactly how you will drive it. You may
drive very short distances only a few times a week.
Or you may drive long distances all the time in
very hot, dusty weather. You may use your vehicle
in making deliveries or in many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may
need more frequent checks and replacements.
So please read the following and note how
you drive. If you have any questions on how to
keep your vehicle in good condition, see your
dealer.
This part tells you the maintenance services you
should have done and when to schedule them.When you go to your dealer for your service
needs, you will know that GM-trained and
supported service people will perform the work
using genuine GM parts.
The proper fluids and lubricants to use are listed
in Part C. Make sure whoever services your
vehicle uses these. All parts should be replaced
and all necessary repairs done before you or
anyone else drives the vehicle.
This schedule is for vehicles that:
•carry passengers and cargo within
recommended limits. You will find limits
on your vehicle’s Certification or Tire
Information label. SeeLoading Your Vehicle
on page 238.
•are driven on reasonable road surfaces within
legal driving limits.
•use the recommended fuel. SeeGasoline
Octane on page 251for gasoline engine
vehicles orWhat Fuel to Use on page 253
for diesel engine vehicles.
362
Page 363 of 430

Scheduled Maintenance
Supplements
If your vehicle has a Caterpillar®diesel engine,
your owner’s manual is supplemented by the
Caterpillar
®Diesel Engine Operation &
Maintenance Manual. If your vehicle has an
Allison Transmission
®, your owner’s manual is
supplemented by an Allison Transmission®
Operator’s Manual. Always refer to these manuals
for related maintenance services.
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 6H 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 276orEngine
Oil Life System (DURAMAX
®Diesel) on page 278
orEngine Oil Life System (Caterpillar®Diesel
Engine) on page 279.
The “Footnotes” at the end of this Maintenance
Schedule further explain maintenance services.
SeeService Publications Ordering Information
on page 415.
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)
363