
2 (Second):This position reduces vehicle speed even
more than 3 (Third) without using the brakes. You
can use 2 (Second) on hills. It can help control vehicle
speed as you go down steep mountain roads, but
then you would also want to use the brakes off and on.
You may use this feature for reducing torque to the
rear wheels when you are trying to start the vehicle from
a stop on slippery road surfaces.
1 (First):This position reduces vehicle speed even
more than 2 (Second) without using the brakes. You can
use it on very steep hills, or in deep snow or mud. If
the shift lever is put in 1 (First) while the vehicle
is moving forward, the transmission will not shift into
first gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on a
hill, use the brakes to hold the vehicle in place.Tow/Haul Mode
Tow/haul is designed to assist while the vehicle is
pulling a large or heavy load or trailer. Tow/haul is most
useful while pulling such a load in rolling terrain, in
stop-and-go traffic, or when you need improved
low-speed control, such as when parking. The purpose
of the tow/haul mode is to:
•Reduce the frequency and improve the predictability
of transmission shifts,
•provide the same solid shift feel when pulling a
heavy load as when the vehicle is unloaded,
•improve control of vehicle speed while requiring
less throttle pedal activity.
Press this button located
to the right of the steering
wheel on the instrument
panel to turn tow/haul
mode on and off.
2-25

Brake Wear
This vehicle has disc brakes. Disc brake pads have
built-in wear indicators that make a high-pitched warning
sound when the brake pads are worn and new pads
are needed. The sound can come and go or be heard all
the time the vehicle is moving, except when applying
the brake pedal firmly.
{CAUTION:
The brake wear warning sound means that soon
the brakes will not work well. That could lead to an
accident. When the brake wear warning sound is
heard, have the vehicle serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.Some driving conditions or climates can cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
the brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to torque specifications in
Capacities and Specifications on page 5-110.
Brake linings should always be replaced as complete
axle sets.Brake Pedal Travel
See your dealer/retailer if the brake pedal does not
return to normal height, or if there is a rapid increase in
pedal travel. This could be a sign that brake service
might be required.
Brake Adjustment
Every brake stop, the brakes adjust for wear.
5-38

How to Check
Use a good quality pocket-type gage to check tire
pressure. You cannot tell if your tires are properly
inflated simply by looking at them. Radial tires
may look properly inflated even when they are
underinflated. Check the tire’s inflation pressure
when the tires are cold. Cold means your vehicle
has been sitting for at least three hours or driven
no more than 1 mile (1.6 km).
Remove the valve cap from the tire valve stem.
Press the tire gage firmly onto the valve to
get a pressure measurement. If the cold tire
inflation pressure matches the recommended
pressure on the Tire and Loading Information
label, no further adjustment is necessary.
If the pressure is low, add air until you reach
the recommended amount.
If you overfill the tire, release air by pushing on
the metal stem in the center of the tire valve.
Recheck the tire pressure with the tire gage.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.
Dual Tire Operation
When the vehicle is new, or whenever a wheel,
wheel bolt or wheel nut is replaced, check the wheel nut
torque after 100, 1,000 and 6,000 miles (160, 1 600 and
10 000 km) of driving. For proper wheel nut tightening
information, see “Removing the Flat Tire and Installing
the Spare Tire” later in this section, underChanging a
Flat Tire on page 5-80. Also see “Wheel Nut Torque”
underCapacities and Specifications on page 5-110.
The outer tire on a dual wheel setup generally wears
faster than the inner tire. Your tires will wear more
evenly and last longer if you rotate the tires periodically.
SeeTire Inspection and Rotation on page 5-70.
Also seeScheduled Maintenance on page 6-4.
{CAUTION:
If you operate your vehicle with a tire that is badly
underinflated, the tire can overheat. An overheated
tire can lose air suddenly or catch fire. You or
others could be injured. Be sure all tires (including
the spare) are properly inflated.
SeeTires on page 5-55andInflation - Tire Pressure on
page 5-63for more information on proper tire inflation.
5-64

SeeInflation - Tire Pressure on page 5-63and
Loading the Vehicle on page 4-18. Make certain
that all wheel nuts are properly tightened.
See “Wheel Nut Torque” underCapacities
and Specifications on page 5-110.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the
vehicle. In an emergency, you can use a cloth
or a paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get all
the rust or dirt off. SeeChanging a Flat Tire on
page 5-80.
If your vehicle has a Tire Pressure Monitor
System (TPMS), reset the TPMS sensors after
rotating the tires. SeeTire Pressure Monitor
Operation on page 5-66.
Make sure the spare tire is stored securely.
Push, pull, and then try to rotate or turn the tire.
If it moves, tighten the cable. SeeStoring a
Flat or Spare Tire and Tools on page 5-94.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
influence when you need new tires.
One way to tell when it
is time for new tires is to
check the treadwear
indicators, which appear
when your tires have only
1/16 inch (1.6 mm) or less
of tread remaining.
Some commercial truck tires, including Goodyear
LT225/75R16 G949 RSA and Goodyear LT225/75R16
G933 RSD, may not have treadwear indicators.
If the tires do not have treadwear indicators, replace
the tires when the tread depth is down to 1/8 inch
(3.2 mm) for the front tires, or 1/16 inch (1.6 mm)
for the rear tires.
5-72

Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were aligned and
balanced carefully at the factory to give you the longest
tire life and best overall performance. Adjustments to
wheel alignment and tire balancing will not be necessary
on a regular basis. However, if you notice unusual tire
wear or your vehicle pulling to one side or the other, the
alignment might need to be checked. If you notice your
vehicle vibrating when driving on a smooth road, the tires
and wheels might need to be rebalanced. See your
dealer/retailer for proper diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep coming loose, the wheel,
wheel bolts and wheel nuts should be replaced. If the
wheel leaks air, replace it (except some aluminum
wheels, which can sometimes be repaired). See your
dealer/retailer if any of these conditions exist.
Your dealer/retailer will know the kind of wheel
you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted
the same way as the one it replaces.
If you need to replace any of the wheels, wheel bolts,
wheel nuts or Tire Pressure Monitor System (TPMS)
sensors, replace them only with new GM originalequipment parts. This way, you will be sure to have the
right wheel, wheel bolts, wheel nuts, and TPMS sensors
for the vehicle.
{CAUTION:
Using the wrong replacement wheels, wheel bolts,
or wheel nuts on your vehicle can be dangerous.
It could affect the braking and handling of your
vehicle, make your tires lose air and make you
lose control. You could have a collision in which
you or others could be injured. Always use the
correct wheel, wheel bolts, and wheel nuts for
replacement.
Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance, and tire or tire chain
clearance to the body and chassis.
Whenever a wheel, wheel bolt or wheel nut is replaced
on a dual wheel setup, check the wheel nut torque after
100, 1,000 and 6,000 miles (160, 1 600 and 10 000 km)
of driving. For proper torque, see “Wheel Nut Torque”
underCapacities and Specifications on page 5-110.
SeeChanging a Flat Tire on page 5-80for more
information.
5-77

{CAUTION:
Wheel nuts that are improperly or incorrectly
tightened can cause the wheels to become loose or
come off. The wheel nuts should be tightened with a
torque wrench to the proper torque specification
after replacing. Follow the torque specification
supplied by the aftermarket manufacturer when
using accessory locking wheel nuts. SeeCapacities
and Specifications on page 5-110for original
equipment wheel nut torque specifications.
Notice:Improperly tightened wheel nuts can
lead to brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper torque
speci cation. SeeCapacities and Specifications on
page 5-110for the wheel nut torque speci cation.11. Use the wheel wrench to tighten the nuts firmly.
Turn the wheel wrench clockwise and in a
crisscross sequence as shown.
12. Put the wheel cover or the center cap and plastic
wheel nut caps back on. Remove any wheel blocks.
Have a technician check the wheel nut tightness
of all wheels with a torque wrench after the first
100 miles (160 km) and then 1,000 miles (1600 km)
after that. Repeat this service whenever you have
a tire removed or serviced. SeeCapacities and
Specifications on page 5-110for more information.
5-90

ApplicationCapacities
English Metric
Fuel Tank
Standard Tank (Passenger and Cargo) 31.0 gal 117.3 L
Standard Tank (Cab and Chassis) 33.0 gal 124.9 L
Optional Tank (Cab and Chassis)* 57.0 gal 215.7 L
* 159 inch (4 039 mm) wheelbase or 177 inch (4 496 mm) wheelbase only
Transmission Fluid
4-SPD 4L60-E 5.0 qt 4.7 L
4-SPD 4L80-E (Standard and Heavy Duty) 7.7 qt 7.3 L
Wheel Nut Torque 140 ft lb 190Y
All capacities are approximate. When adding, be sure to fill to the approximate level, as recommended in this
manual. Recheck fluid level after filling.
Engine Speci cations
Engine VIN Code Transmission Spark Plug Gap
4.3L V6 X Automatic 0.060 in (1.52 mm)
4.8L V8 C Automatic 0.040 in (1.01 mm)
5.3L V8 4 Automatic 0.040 in (1.01 mm)
6.0L V8 K Automatic 0.040 in (1.01 mm)
5-111

Owner Checks and Services
These owner checks and services should be performed
at the intervals specified to help ensure vehicle safety,
dependability, and emission control performance. Your
dealer/retailer can assist with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any fluids or lubricants are added to the
vehicle, make sure they are the proper ones, as shown
inRecommended Fluids and Lubricants on page 6-14.
At the First 100, 1,000 and
6,000 Miles (160, 1 600 and
10 000 km)
For vehicles with dual wheels, check dual wheel nut
torque. For proper torque, seeCapacities and
Specifications on page 5-110.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel fill.
Engine Oil Level Check
Notice:It is important to check the engine oil
regularly and keep it at the proper level. Failure to
keep the engine oil at the proper level can cause
damage to the engine not covered by the vehicle
warranty.
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-15.
Engine Coolant Level Check
Check the engine coolant level and add DEX-COOL®
coolant mixture if necessary. SeeEngine Coolant
on page 5-25.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the windshield
washer fluid reservoir and add the proper fluid if
necessary.
6-10