wheel GMC ENVOY DENALI 2008 Repair Manual

{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P).
You or others could be injured. Make sure the
parking brake is rmly set before you shift the
transfer case to NEUTRAL.
6. Shift the transfer case to NEUTRAL (N). See
Four-Wheel Drive on page 2-29for the proper
procedure to select the NEUTRAL (N) position for
your vehicle.
7. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle.
8. Turn the ignition off.
After towing, see “Shifting Out of Neutral” under
Four-Wheel Drive on page 2-29.
Rear Towing (Rear Wheels Off
the Ground)
(Two-Wheel or Four-Wheel-Drive Vehicles)
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-33for more information.
3. Shift the transmission in PARK (P).
4-43

4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle. Use an adequate clamping device to ensure
that the front wheels are locked into the straight
position.
5. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle.
6. Turn the ignition to LOCK.
If the tow vehicle will not be started or driven for
six weeks or more, remove the battery cable
from the negative terminal (post) of the battery.
Electronically Controlled Air
Suspension System
Your vehicle may be equipped with an electronically
controlled air suspension system that automatically
keeps your vehicle level as you load and unload.
The system includes a compressor, two height
sensors and two air springs supporting the rear axle.The system also has an internal clock to prevent
overheating if the inator is used for prolonged periods.
If the system overheats, all leveling function stops
until the system cools down. During this time, the
indicator light on the air inator switch will be ashing.
The ignition has to be on for the system to inate,
in order to raise the vehicle to the standard ride height
after loading. The system can lower the vehicle to
the standard ride height after unloading with the ignition
on and also for up to 30 minutes after the ignition
has been turned off.
You may hear the compressor operating when you load
your vehicle, and periodically as the system adjusts
the vehicle to the standard ride height.
Load leveling will not function normally with the inator
hose attached to the inator outlet. Remove the inator
hose from the outlet during loading and unloading.
If the vehicle is parked for an extended period of time,
some bleed down of the suspension is normal. Upon
starting the vehicle, proper height will be achieved.
4-44

Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good
deal longer, you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just move that hand
to the left. To move the trailer to the right, move your
hand to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns than
normal. Do this so your trailer won’t strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ash, telling other drivers
you’re about to turn, change lanes or stop.When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift down,
you might have to use your brakes so much that they
would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or a lower gear, under heavy
loads or hilly conditions.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do
get the overheat warning, seeEngine Overheating
on page 5-28.
4-53

Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake, and then shift into PARK (P).
5. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P) with
the parking brake rmly set.
If the transfer case on four-wheel drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not
in NEUTRAL.
SeeFour-Wheel Drive on page 2-29.
4-54

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-16
Engine Oil Life System..................................5-19
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-23
Engine Coolant.............................................5-26
Radiator Pressure Cap..................................5-28
Engine Overheating.......................................5-28
Cooling System............................................5-30Engine Fan Noise.........................................5-35
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-37
Brakes........................................................5-38
Battery........................................................5-41
Jump Starting...............................................5-42
Rear Axle.......................................................5-46
Four-Wheel Drive............................................5-47
Front Axle......................................................5-48
Headlamp Aiming...........................................5-49
Bulb Replacement..........................................5-49
Halogen Bulbs..............................................5-49
Headlamps..................................................5-50
Front Turn Signal, Sidemarker and
Parking Lamps..........................................5-51
Taillamps, Turn Signal, and Stoplamps............5-51
Back-Up Lamps............................................5-53
License Plate Lamp......................................5-53
Replacement Bulbs.......................................5-54
Windshield Wiper Blade Replacement..............5-54
Tires..............................................................5-57
Tire Sidewall Labeling...................................5-58
Tire Terminology and Denitions.....................5-61
Ination - Tire Pressure.................................5-64
Section 5 Service and Appearance Care
5-1

High-Speed Operation...................................5-66
Tire Pressure Monitor System.........................5-67
Tire Pressure Monitor Operation.....................5-69
Tire Inspection and Rotation...........................5-72
When It Is Time for New Tires.......................5-73
Buying New Tires.........................................5-74
Different Size Tires and Wheels......................5-76
Uniform Tire Quality Grading..........................5-77
Wheel Alignment and Tire Balance..................5-78
Wheel Replacement......................................5-78
Tire Chains..................................................5-80
Accessory Inator.........................................5-80
If a Tire Goes Flat........................................5-81
Changing a Flat Tire.....................................5-82
Removing the Spare Tire and Tools................5-84
Removing the Flat Tire and Installing the
Spare Tire................................................5-87
Secondary Latch System...............................5-92
Storing a Flat or Spare Tire and Tools............5-96
Spare Tire...................................................5-99
Appearance Care..........................................5-100
Interior Cleaning.........................................5-100
Fabric/Carpet..............................................5-101
Leather......................................................5-102
Instrument Panel, Vinyl, and Other
Plastic Surfaces.......................................5-102Care of Safety Belts....................................5-103
Weatherstrips.............................................5-103
Washing Your Vehicle..................................5-103
Cleaning Exterior Lamps/Lenses....................5-104
Finish Care................................................5-104
Windshield, Backglass, and Wiper Blades.......5-105
Aluminum Wheels.......................................5-105
Tires.........................................................5-106
Sheet Metal Damage...................................5-106
Finish Damage...........................................5-106
Underbody Maintenance...............................5-106
Chemical Paint Spotting...............................5-106
Vehicle Care/Appearance Materials................5-107
Vehicle Identication.....................................5-108
Vehicle Identication Number (VIN)................5-108
Service Parts Identication Label...................5-108
Electrical System..........................................5-109
Add-On Electrical Equipment.........................5-109
Headlamps.................................................5-109
Windshield Wiper Fuses...............................5-109
Power Windows and Other Power Options......5-109
Fuses and Circuit Breakers..........................5-110
Engine Compartment Fuse Block...................5-110
Rear Underseat Fuse Block..........................5-116
Capacities and Specications........................5-120
Section 5 Service and Appearance Care
5-2

Brake Wear
Your 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 your vehicle is moving, except when you are
pushing on the brake pedal rmly.
{CAUTION:
The brake wear warning sound means that
soon the brakes will not work well. That could
lead to an accident. When you hear the brake
wear warning sound, have your 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 rst 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 specications in
Capacities and Specifications on page 5-120.
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 time you make a brake stop, the disc brakes
adjust for wear.
5-40

Jump Starting
If your vehicle’s battery has run down, you may want to
use another vehicle and some jumper cables to start
your vehicle. Be sure to use the following steps to do it
safely.
{CAUTION:
Batteries can hurt you. They can be dangerous
because:
They contain acid that can burn you.
They contain gas that can explode or
ignite.
They contain enough electricity to
burn you.
If you do not follow these steps exactly, some
or all of these things can hurt you.Notice:Ignoring these steps could result in costly
damage to your vehicle that would not be covered
by your warranty.
Your vehicle cannot be started by pushing or
pulling it, and can be damage by trying it.
1. Check the other vehicle. It must have a 12-volt
battery with a negative ground system.
Notice:If the other vehicle’s system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles are not touching
each other. If they are, it could cause a ground
connection you do not want. You would not be able
to start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake rmly on both vehicles involved
in the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
If you have a four-wheel-drive vehicle, be sure
the transfer case is not in NEUTRAL.
5-42

How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
The proper level is from 0 to 0.40 inch (0 to 10 mm)
below the bottom of the ller plug hole, located on the
rear axle.
What to Use
To determine what kind of lubricant to use, see
Recommended Fluids and Lubricants on page 6-12.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
It is not necessary to regularly check uid unless you
suspect there is a leak or you hear an unusual noise.
A uid loss could indicate a problem. Have it inspected
and repaired.
How to Check Lubricant
To get an accurate
reading, the vehicle should
be on a level surface.
If the level is below the bottom of the ller plug hole,
you will need to add some lubricant. Add enough
lubricant to raise the level to the bottom of the ller plug
hole. Use care not to overtighten the plug.
5-47

Low-Prole Performance Tire
If your vehicle has P255/50R20 size tires, they are
classied as low-prole performance tires. These
tires are designed for very responsive driving on
wet or dry pavement. You may also notice more
road noise with low-prole performance tires and
that they tend to wear faster.
Notice:If your vehicle has low-prole tires,
they are more susceptible to damage from road
hazards or curb impact than standard prole
tires. Tire and/or wheel assembly damage can
occur when coming into contact with road
hazards like, potholes, or sharp edged objects,
or when sliding into a curb. Your vehicle
warranty does not cover this type of damage.
Keep tires set to the correct ination pressure
and, when possible avoid contact with curbs,
potholes, and other road hazards.
Tire Sidewall Labeling
Useful information about a tire is molded into the
sidewall. The following illustration is an example
of a typical P-Metric tire sidewall.
(A) Tire Size
:The tire size code is a combination
of letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction type,
and service description. See the “Tire Size”
illustration later in this section for more detail.
Passenger (P-Metric) Tire
5-58