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(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 75, as
shown in item C of the illustration, it would mean
that the tire’s sidewall is 75 percent as high as it
is wide.
(D) Construction Code
:A letter code is used to
indicate the type of ply construction in the tire. The
letter R means radial ply construction; the letter D
means diagonal or bias ply construction; and the
letter B means belted-bias ply construction.
(E) Rim Diameter
:Diameter of the wheel in
inches.
(F) Service Description
:These characters
represent the load index and speed rating of the
tire. The load index represents the load carry
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified
to carry a load.(A) Light Truck (LT-Metric) Tire
:The United
States version of a metric tire sizing system.
The letters LT as the first two characters in the
tire size means a light truck tire engineered
to standards set by the U.S. Tire and Rim
Association.
(B) Tire Width
:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio
:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 75, as
shown in item C of the light truck (LT-Metric) tire
illustration, it would mean that the tire’s sidewall is
75 percent as high as it is wide.
Light Truck (LT-Metric) Tire
6-64
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(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The
letter R means radial ply construction; the letter D
means diagonal or bias ply construction; and the
letter B means belted-bias ply construction.
(E) Rim Diameter
:Diameter of the wheel in
inches.
(F) Load Range
:Load Range.
(G) Service Description
:The service description
indicates the load index and speed rating of a tire.
If two numbers are given as in the example,
120/116, then this represents the load index for
single versus dual wheel usage (single/dual).
The speed rating is the maximum speed a tire is
certified to carry a load. This does not apply to
Goodyear LT225/75R16 G949 RSA and Goodyear
LT225/75R16 G933 RSD commercial truck tires;
see the dual tire and single tire maximum load and
load range letter designations on the tire sidewall.
Tire Terminology and De nitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of
the tire. Air pressure is expressed in pounds
per square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, power windows,
power seats, and air conditioning.
Aspect Ratio
:The relationship of a tire’s height
to its width.
Belt
:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead
:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
Bias Ply Tire
:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.
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Buying New Tires
GM has developed and matched specific tires for your
vehicle. The original equipment tires installed on your
vehicle, when it was new, were designed to meet
General Motors Tire Performance Criteria Specification
(TPC spec) system rating. If you need replacement tires,
GM strongly recommends that you get tires with the same
TPC Spec rating. This way, your vehicle will continue
to have tires that are designed to give the same
performance and vehicle safety, during normal use,
as the original tires.
GM’s exclusive TPC Spec system considers over a
dozen critical specifications that impact the overall
performance of your vehicle, including brake system
performance, ride and handling, traction control, and
tire pressure monitoring performance. GM’s TPC Spec
number is molded onto the tire’s sidewall near the tire
size. If the tires have an all-season tread design, the TPC
spec number will be followed by a MS, for mud and snow.
SeeTire Sidewall Labeling on page 6-61for additional
information.
GM recommends replacing tires in sets of four (or six
if your vehicle has dual rear wheels). This is because
uniform tread depth on all tires will help keep your vehicle
performing most like it did when the tires were new.
Replacing less than a full set of tires can affect the
braking and handling performance of your vehicle.
SeeTire Inspection and Rotation on page 6-75for
information on proper tire rotation.{WARNING:
Mixing tires could cause you to lose control
while driving. If you mix tires of different
sizes, brands, or types (radial and bias-belted
tires) the vehicle may not handle properly,
and you could have a crash. Using tires of
different sizes, brands, or types may also
cause damage to your vehicle. Be sure to
use the correct size, brand, and type of tires
on your vehicle’s wheels.
{WARNING:
If you use bias-ply tires on the vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash. Use only
radial-ply tires with the wheels on the vehicle.
If you must replace your vehicle’s tires with those that do
not have a TPC Spec number, make sure they are the
same size, load range, speed rating, and construction
type (radial and bias-belted tires) as your vehicle’s
original tires.
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Page 374 of 440

If any of the soil remains, a commercial fabric cleaner
or spot lifter may be necessary. When a commercial
upholstery cleaner or spot lifter is to be used, test
a small hidden area for colorfastness first. If the
locally cleaned area gives any impression that a
ring formation may result, clean the entire surface.
After the cleaning process has been completed, a paper
towel can be used to blot excess moisture from the
fabric or carpet.
Instrument Panel, Vinyl, and Other
Plastic Surfaces
A soft cloth dampened with water may be used to remove
dust. If a more thorough cleaning is necessary, a clean
soft cloth dampened with a mild soap solution can be
used to gently remove dust and dirt. Never use spot lifters
or removers on plastic surfaces. Many commercial
cleaners and coatings that are sold to preserve and
protect soft plastic surfaces may permanently change
the appearance and feel of the interior and are not
recommended. Do not use silicone or wax-basedproducts, or those containing organic solvents to
clean the vehicle’s interior because they can alter the
appearance by increasing the gloss in a non-uniform
manner.
Some commercial products may increase gloss on the
instrument panel. The increase in gloss may cause
annoying reflections in the windshield and even make
it difficult to see through the windshield under certain
conditions.
Care of Safety Belts
Keep belts clean and dry.
{WARNING:
Do not bleach or dye safety belts. It may severely
weaken them. In a crash, they might not be able
to provide adequate protection. Clean safety belts
only with mild soap and lukewarm water.
6-104
Page 389 of 440
Maintenance Schedule......................................7-2
Introduction...................................................7-2
Scheduled Maintenance...................................7-3
Owner Checks and Services..........................7-10Recommended Fluids and Lubricants...............7-12
Maintenance Replacement Parts.....................7-14
Engine Drive Belt Routing..............................7-15
Maintenance Record.....................................7-16
Section 7 Maintenance Schedule
7-1
Page 396 of 440

First Engine Oil Change After Every
160 000 km/100,000 Miles
•
Automatic transmission fluid change (normal
service). SeeAutomatic Transmission Fluid
(4-Speed Transmission) on page 6-21orAutomatic
Transmission Fluid (6-Speed Transmission) on
page 6-24.
•All-wheel drive only: Transfer case fluid change
(normal service). Check vent hose at transfer
case for kinks and proper installation. Check to be
sure vent hose is unobstructed, clear, and free
of debris. During any maintenance, if a power
washer is used to clean mud and dirt from the
underbody, care should be taken to not directly
spray the transfer case output seals. High pressure
water can overcome the seals and contaminate
the transfer case fluid. Contaminated fluid will
decrease the life of the transfer case and should
be replaced.
•Spark plug replacement and spark plug wires
inspection.An Emission Control Service.
First Engine Oil Change After Every
240 000 km/150,000 Miles
•
Engine cooling system drain, flush, and refill,
cooling system and cap pressure check, and
cleaning of outside of radiator and air conditioning
condenser (or every 5 years, whichever occurs
first). SeeEngine Coolant on page 6-29.
An Emission Control Service.
•Engine accessory drive belt inspection for fraying,
excessive cracks, or obvious damage and
replacement, if needed.An Emission Control
Service.
7-8
Page 403 of 440
Engine Drive Belt Routing
If your vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information. V6 Engines
V8 Engines
7-15
Page 424 of 440

Vehicle Data Recording and
Privacy
Your GM vehicle has a number of sophisticated
computers that record information about the vehicle’s
performance and how it is driven. For example, your
vehicle uses computer modules to monitor and control
engine and transmission performance, to monitor the
conditions for airbag deployment and deploy airbags
in a crash and, if so equipped, to provide antilock braking
to help the driver control the vehicle. These modules may
store data to help your dealer/retailer technician service
your vehicle. Some modules may also store data about
how you operate the vehicle, such as rate of fuel
consumption or average speed. These modules may also
retain the owner’s personal preferences, such as radio
pre-sets, seat positions, and temperature settings.
Event Data Recorders
This vehicle has an Event Data Recorder (EDR).
The main purpose of an EDR is to record, in certain
crash or near crash-like situations, such as an airbag
deployment or hitting a road obstacle, data that will assist
in understanding how a vehicle’s systems performed.
The EDR is designed to record data related to vehicle
dynamics and safety systems for a short period of time,
typically 30 seconds or less. The EDR in this vehicle is
designed to record such data as:
•How various systems in your vehicle were operating
•Whether or not the driver and passenger safety belts
were buckled/fastened
•How far, if at all, the driver was pressing the
accelerator and/or brake pedal
•How fast the vehicle was traveling
This data can help provide a better understanding of the
circumstances in which crashes and injuries occur.
8-18