spare tire GMC ENVOY 2003 Owner's Manual

Off-Road Driving with Your
Four-Wheel-Drive Vehicle
This off-road guide is for vehicles that have four-wheel
drive. Also, seeBraking on page 4-5. If your vehicle
doesn't have four-wheel drive, you shouldn't drive
off-road unless you're on a level, solid surface.
Off-road driving can be great fun. But it does have
some de®nite hazards. The greatest of these is
the terrain itself.
ªOff-roadingº means you've left the great North American
road system behind. Traffic lanes aren't marked.
Curves aren't banked. There are no road signs.
Surfaces can be slippery, rough, uphill or downhill. In
short, you've gone right back to nature.
Off-road driving involves some new skills. And that's
why it's very important that you read this guide.
You'll ®nd many driving tips and suggestions. These will
help make your off-road driving safer and more
enjoyable.
Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance
and service work done. Check to make sure all
underbody shields (if so equipped) are properly
attached.
Be sure you read all the information about your
four-wheel-drive vehicle in this manual.
Is there enough fuel? Is the spare tire fully in¯ated? Are
the ¯uid levels up where they should be? What are
the local laws that apply to off-roading where you'll be
driving? If you don't know, you should check with
law enforcement people in the area. Will you be on
someone's private land? If so, be sure to get the
necessary permission.
4-15

In¯ation -- Tire Pressure
The Certi®cation/Tire label, which is on the driver's door
edge, above the door latch, shows the correct in¯ation
pressures for your tires when they're cold. ªColdº means
your vehicle has been sitting for at least three hours
or driven no more than 1 mile (1.6 km).
Notice:Don't let anyone tell you that underin¯ation
or overin¯ation is all right. It's not. If your tires
don't have enough air (underin¯ation), you can get
the following:
·Too much ¯exing
·Too much heat
·Tire overloading
·Bad wear
·Bad handling
·Bad fuel economy
If your tires have too much air (overin¯ation), you
can get the following:
·Unusual wear
·Bad handling
·Rough ride
·Needless damage from road hazards
When to Check
Check your tires once a month or more.
Also, check the tire pressure of the spare tire.
How to Check
Use a good quality pocket-type gage to check tire
pressure. You can't tell if your tires are properly in¯ated
simply by looking at them. Radial tires may look
properly in¯ated even when they're underin¯ated.
Be sure to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt and
moisture.
Tire Inspection and Rotation
Tires should be rotated every 7,500 miles (12 500 km).
Any time you notice unusual wear, rotate your tires
as soon as possible and check wheel alignment. Also
check for damaged tires or wheels. See
When It Is Time
for New Tires on page 5-57andWheel Replacement
on page 5-60for more information.
Make sure the spare tire is stored securely. Push, pull,
and then try to rotate or turn the tire. If it moves,
use the wheel wrench to tighten the cable. See
Changing a Flat Tire on page 5-64.
5-55

Uniform Tire Quality Grading
Quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance. (This
applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter-type
snow tires, space-saver or temporary use spare tires,
tires with nominal rim diameters of 10 to 12 inches
(25 to 30 cm), or to some limited-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.
Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a speci®ed government test course.
For example, a tire graded 150 would wear one and
a half (1.5) times as well on the government course as
a tire graded 100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart signi®cantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction ± AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire's ability
to stop on wet pavement as measured under controlled
conditions on speci®ed government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.
5-59

Removing the Spare Tire and Tools
The jacking equipment you will need is stored under the
rear seat in the Envoy or in the left rear quarter panel
storage compartment in the Envoy XL. To release
the jack from its holder, turn the knob on the jack
counterclockwise to lower the jack head. See
Rear Seat
Operation on page 1-6for more information. Envoy
Envoy XL
5-66

The tools you'll be using include the wheel wrench (A),
tire blocks (B), extension(s) (socket end) (C), handle
(jack end) (D), and jack (E).
The following instructions explain how to remove the
spare tire mounted underneath your vehicle.
Notice:Never remove or restow a tire from/to a
storage position under the vehicle while the vehicle
is supported by a jack. Always tighten the tire
fully against the underside of the vehicle when
restowing.1. To remove the underbody-mounted spare, insert
the socket end of the extension on a 45É angle
downward into the hoist drive shaft hole. It is
exposed when the rear gate is open and is just
above the rear bumper. Be sure the socket end of
the extension connects into the hoist shaft.
5-67

2. Turn the wheel wrench counterclockwise to lower
the spare tire. Keep turning the wheel wrench until
the spare tire can be pulled out from under the
vehicle.
If the spare tire does not lower to the ground, the
secondary latch is engaged causing the tire
not to lower. See ªSecondary Latch Systemº later in
this section.
When the tire has been completely lowered, tilt the
retainer at the end of the cable and pull it through
the wheel opening. Pull the tire out from under
the vehicle.
Notice:To help avoid vehicle damage, do not drive
the vehicle before the cable is restored.
3. Put the spare tire near the ¯at tire.4. Use the chisel end of the wheel wrench to pry off
the center cap.
See ªRemoving the Flat Tire and Installing the Spare
Tireº later in this section to continue changing the
¯at tire.
5-68

Secondary Latch System
Your vehicle has an underbody mounted tire hoist
assembly equipped with a secondary latch system. It's
designed to stop the spare or ¯at road tire from
suddenly falling off your vehicle if the cable holding the
spare tire is damaged. For the secondary latch to
work, the spare tire must be stored with the valve stem
pointing up. See ªStoring a Flat or Spare Tire and
Toolsº for instructions on storing the spare tire correctly.
{CAUTION:
Before beginning this procedure read all the
instructions. Failure to read and follow the
instructions could damage the hoist assembly
and you and others could get hurt. Read and
follow the instructions listed below.
{CAUTION:
Someone standing too close during the
procedure could be injured by the jack. If the
spare tire does not slide off the jack
completely, make sure no one is behind you or
on either side of you as you pull the jack out
from the spare.
To release the spare tire from the secondary latch do
the following:
1. Check under the
vehicle to see if
the cable is visible.
5-69

2. If it is not visible, proceed to Step 6.
If visible, ®rst try to tighten the cable by turning the
wheel wrench clockwise until you hear two clicks
or feel it skip twice. You cannot overtighten
the cable.
3. Loosen the cable by turning the wheel wrench
counterclockwise three or four turns.
4. Repeat this procedure at least two times.
If the spare tire lowers to the ground, continue with
Step 2 of ªRemoving the Spare Tire and Toolsº
earlier in this section.
5. Turn the wrench counterclockwise until
approximately 6 inches (15 cm) of cable is exposed.
6. Attach the jack handle, extension and the wheel
wrench to the jack and place it under the vehicle
towards the front of the rear bumper. Position
the center lift point of the jack under the center of
the spare tire.
7. Turn the wrench clockwise to raise the jack until it
lifts the end ®tting.
8. Continue raising the jack until the spare tire stops
moving upward and is held ®rmly in place. The
secondary latch has released and the spare tire is
balancing on the jack.
5-70

9. Lower the jack by turning the wheel wrench
counterclockwise. Keep lowering the jack until the
spare tire slides off the jack or is hanging by
the cable.
10. Disconnect the jack handle from the jack and
carefully remove the jack. Use one hand to
push against the spare while ®rmly pulling the jack
out from under the spare tire with the other
hand.If the spare tire is hanging from the cable, insert the
jack handle, extension and wheel wrench into the
hoist shaft hole in the bumper, on an angle, and turn
the wheel wrench counterclockwise to lower the
spare the rest of the way.
11. Tilt the retainer at the end of the cable and pull it
through the wheel opening. Pull the tire out from
under the vehicle.
12. If the cable is hanging under the vehicle, turn the
wheel wrench in the hoist shaft hole in the bumper
clockwise to raise the cable back up.
Have the hoist assembly inspected as soon as you can.
You will not be able to store a spare or ¯at tire using
the hoist assembly until it has been repaired or replaced.
5-71

Removing the Flat Tire and Installing
the Spare Tire
1. Using the wheel wrench, loosen all the wheel nuts.
Don't remove them yet.
2. Turn the jack adjusting knob clockwise by hand to
raise the jack lift head.3. Place the handle, extension and wheel wrench onto
the jack.
Front
5-72