height GMC SIERRA CLASSIC 2007 Owners Manual

Head Restraints
Adjust the head restraint so that the top of the
restraint is at the same height as the occupant’s
head. This position reduces the chance of a
neck injury in a crash.
Pull the head restraint up to raise it. Push the
head restraint down to lower it.
The rear seats may have head restraints that can
be adjusted up and down.
Seatback Latches
The front seatbacks fold forward to allow access
to the rear of the cab.
To fold the seatback forward, lift the lever located
on the outboard side of the seat cushion.
{CAUTION:
If the seatback is not locked, it could
move forward in a sudden stop or crash.
That could cause injury to the person
sitting there. Always push and pull on the
seatback to be sure it is locked.
To return the seatback to the upright position,
push the seatback rearward until it latches. After
returning the seatback to its upright position,
push and pull on the seatback to make sure it is
locked.
18

Q:What are the different types of add-on
child restraints?
A:Add-on child restraints, which are purchased by
the vehicle’s owner, are available in four basic
types. Selection of a particular restraint should
take into consideration not only the child’s
weight, height, and age but also whether or not
the restraint will be compatible with the motor
vehicle in which it will be used.
For most basic types of child restraints, there
are many different models available. When
purchasing a child restraint, be sure it is
designed to be used in a motor vehicle. If it is,
the restraint will have a label saying that it
meets federal motor vehicle safety standards.
The restraint manufacturer’s instructions that
come with the restraint state the weight and
height limitations for a particular child restraint.
In addition, there are many kinds of restraints
available for children with special needs.
{CAUTION:
Newborn infants need complete support,
including support for the head and neck.
This is necessary because a newborn
infant’s neck is weak and its head weighs
so much compared with the rest of its
body. In a crash, an infant in a rear-facing
seat settles into the restraint, so the crash
forces can be distributed across the
strongest part of an infant’s body, the
back and shoulders. Infants always
should be secured in appropriate infant
restraints.
50

{CAUTION:
For up to 10 seconds after the ignition key
is turned off and the battery is
disconnected, an airbag can still inate
during improper service. You can be
injured if you are close to an airbag when
it inates. Avoid yellow connectors. They
are probably part of the airbag system. Be
sure to follow proper service procedures,
and make sure the person performing
work for you is qualied to do so.
The airbag system does not need regular
maintenance.
Adding Equipment to Your
Airbag-Equipped Vehicle
Q:Is there anything I might add to the front of
the vehicle that could keep the airbags
from working properly?
A:Yes. If you add things that change your
vehicle’s frame, bumper system, height,
front end or side sheet metal, they may keep
the airbag system from working properly.
Also, the airbag system may not work properly
if you relocate any of the airbag sensors. If
you have any questions about this, you should
contact Customer Assistance before you
modify your vehicle. The phone numbers and
addresses for Customer Assistance are in
Step Two of the Customer Satisfaction
Procedure in this manual. SeeCustomer
Satisfaction Procedure on page 638.
109

Two-Tiered Loading
By positioning four 2 inches (5 cm) by 6 inches
(15 cm) wooden planks across the width of
the pickup box, you can create an upper load
platform. The planks must be inserted in the pickup
box depressions. The length of the planks must
allow for at least a 3/4 inch (2 cm) bearing surface
on each end of the plank.
When using this upper load platform, be sure the
load is securely tied down to prevent it from
shifting. The load’s center of gravity should be
positioned in a zone over the rear axle. The zone
is located in the area between the front of each
wheel well and the rear of each wheel well.
The center of gravity height must not extend above
the top of the pickup box areboard.
Any load that extends beyond the vehicle’s
taillamp area must be properly marked according
to local laws and regulations.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle.
Add-On Equipment
When you carry removable items, you may need
to put a limit on how many people you carry
inside your vehicle. Be sure to weigh your vehicle
before you buy and install the new equipment.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Remember not to exceed the Gross Axle Weight
Rating (GAWR) of the front or rear axle.
*Equipment Maximum Weight
Ladder Rack and Cargo 750 lbs (340 kg)
Cross Toolbox and Cargo 400 lbs (181 kg)
Side Boxes and Cargo 250 lbs per side
(113 kg per side)
*The combined weight for all rail-mounted equipment
should not exceed 1,000 lbs (454 kg), excluded
1500 crew cab models with 5 ft 8 in (173 cm) box
length. A reinforcement kit for rail-mounted add-on
equipment is recommended. See your dealer.
Ladder racks are not recommended for 1500 crew
cab models with 5 ft 8 in (173 cm) pick-up box length.
Maximum recommended cross-mounted toolbox and
cargo weight is 300 lbs (136 kg) for the 1500 crew
cab with 5 ft 8 in (173 cm) pick-up box length.
415

Brake Wear
Your vehicle has front disc brakes and may have
rear drum brakes or rear 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 may 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 your 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 may cause
a brake squeal when the brakes are rst applied or
lightly applied. This does not mean something is
wrong with your 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 GM torque
specications.
If you have rear drum brakes, they do not have
wear indicators, but if you ever hear a rear brake
rubbing noise, have the rear brake linings
inspected immediately. Rear brake drums should
be removed and inspected each time the tires
are removed for rotation or changing. Drum brakes
have an inspection hole to inspect lining wear
during scheduled maintenance. When you have
the front brake pads replaced, have the rear
brakes inspected, too.
Brake linings should always be replaced as
complete axle sets.
Brake Pedal Travel
See your dealer 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 of brake trouble.
Brake Adjustment
Every time you make a brake stop, your brakes
adjust for wear.
519

20-Inch Tires
If your vehicle has the optional 20-inch
P275/55R20 size tires, they are classied as
touring tires and are designed for on road use. The
low-prole, wide tread design is not recommended
for “off-road” driving or commercial uses such
as snow plowing. SeeOff-Road Driving on
page 372andAdding a Snow Plow or Similar
Equipment on page 416for additional information.
Tire Sidewall Labeling
Useful information about a tire is molded into the
sidewall. The following illustrations are examples
of a typical P-Metric and a LT-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
544

(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.(B) TPC Spec (Tire Performance Criteria
Specication):Original equipment tires designed
to GM’s specic tire performance criteria have
a TPC specication code molded onto the sidewall.
GM’s TPC specications meet or exceed all
federal safety guidelines.
(C) Dual Tire Maximum Load:Maximum load
that can be carried and the maximum pressure
needed to support that load when used in a dual
conguration. For information on recommended
tire pressure seeInation - Tire Pressure on
page 551andLoading Your Vehicle on page 409.
(D) DOT (Department of Transportation):The
Department of Transportation (DOT) code
indicates that the tire is in compliance with the
U.S. Department of Transportation Motor Vehicle
Safety Standards.
(E) Tire Identication Number (TIN):The letters
and numbers following DOT code are the Tire
Identication Number (TIN). The TIN shows
the manufacturer and plant code, tire size, and
date the tire was manufactured. The TIN is
molded onto both sides of the tire, although only
one side may have the date of manufacture.
Light Truck (LT-Metric) Tire
546

(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.
(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:The service description
indicates the load range and speed rating of a
tire. The load index can range from 1 to 279.
Speed ratings range from A to Z.Tire Terminology and Denitions
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/
transaxle, 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.
548

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 your wheels, wheel
bolts or wheel nuts, replace them only with
new GM original equipment parts. This way,
you will be sure to have the right wheel, wheel
bolts and wheel nuts for your 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 Specications on page 609.
SeeChanging a Flat Tire on page 564for more
information.
561