suspension GMC SIERRA CLASSIC 2007 Owners Manual

After Off-Road Driving
Remove any brush or debris that has collected
on the underbody, chassis, or under the hood.
These accumulations can be a re hazard.
After operation in mud or sand, have the brake
linings cleaned and checked. These substances
can cause glazing and uneven braking. Check the
body structure, steering, suspension, wheels,
tires, and exhaust system for damage. Also, check
the fuel lines and cooling system for any leakage.
Your vehicle will require more frequent service
due to off-road use. Refer to the Maintenance
Schedule for additional information.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to
be impaired — by alcohol or drugs, with night
vision problems, or by fatigue.
Here are some tips on night driving.
Drive defensively.
Do not drink and drive.
Adjust the inside rearview mirror to reduce the
glare from headlamps behind you.
Since you cannot see as well, you may need
to slow down and keep more space between
you and other vehicles.
Slow down, especially on higher speed roads.
Your vehicle’s headlamps can light up only so
much road ahead.
In remote areas, watch for animals.
If you are tired, pull off the road in a safe
place and rest.
No one can see as well at night as in the daytime.
But as we get older these differences increase.
A 50-year-old driver may require at least twice as
much light to see the same thing at night as a
20-year-old.
What you do in the daytime can also affect your
night vision. For example, if you spend the
day in bright sunshine you are wise to wear
sunglasses. Your eyes will have less trouble
adjusting to night. But if you are driving, do not
wear sunglasses at night. They may cut down on
glare from headlamps, but they also make a
lot of things invisible.
391

To nd out the actual loads on your front and rear
axles, you need to go to a weigh station and weigh
your vehicle. Your dealer can help you with this.
Be sure to spread out your load equally on both
sides of the centerline.
Never exceed the GVWR for your vehicle, or the
GAWR for either the front or rear axle.
The Certication/Tire label also contains important
information about your Front Axle Reserve
Capacity. See “What is front axle reserve capacity,
and how do I calculate it?” underAdding a Snow
Plow or Similar Equipment on page 416.
{CAUTION:
In the case of a sudden stop or collision,
things carried in the bed of your truck
could shift forward and come into the
passenger area, injuring you and others.
If you put things in the bed of your truck,
you should make sure they are properly
secured.
{CAUTION:
Do not load your vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do,
parts on your vehicle can break, and it
can change the way your vehicle handles.
These could cause you to lose control
and crash. Also, overloading can shorten
the life of your vehicle.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
Using heavier suspension components to get
added durability might not change your weight
ratings. Ask your dealer to help you load
your vehicle the right way.
413

Tow/Haul is designed to be most effective when
the vehicle and trailer combined weight is at
least 75 percent of the vehicle’s Gross Combined
Weight Rating (GCWR). See “Weight of the
Trailer” later in the section. Tow/Haul is most
useful under the following driving conditions:
When pulling a heavy trailer or a large
or heavy load through rolling terrain.
When pulling a heavy trailer or a large or
heavy load in stop and go traffic.
When pulling a heavy trailer or a large or
heavy load in busy parking lots where
improved low speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul when lightly
loaded or with no trailer at all will not cause
damage. However, there is no benet to the
selection of Tow/Haul when the vehicle is
unloaded. Such a selection when unloaded may
result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a
heavy trailer or a large or heavy load.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig.
For example, speed, altitude, road grades, outside
temperature and how much your vehicle is used
to pull a trailer are all important. It can also depend
on any special equipment that you have on your
vehicle, and the amount of tongue weight the
vehicle can carry. See “Weight of the Trailer
Tongue” later in this section for more information.
Maximum trailer weight is calculated assuming
only the driver is in the tow vehicle and it has all
the required trailering equipment. The weight
of additional optional equipment, passengers and
cargo in the tow vehicle must be subtracted
from the maximum trailer weight.
Above the 5,000 lbs (2 268 kg) trailer rating,
the handling/trailering suspension is required on
two-wheel drive 1500 series models and the
handling/trailering or off-road suspension is
required on four-wheel drive 1500 series models.
431

Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You cannot know how it has
been used or how far it has been driven. It
could fail suddenly and cause a crash. If
you have to replace a wheel, use a new
GM original equipment wheel.
Tire Chains
{CAUTION:
If your vehicle has dual wheels or
P265/75R16, LT265/75R16, P265/70R17 or
P275/55R20 size tires, do not use tire
chains. They can damage your vehicle
because there is not enough clearance.
Tire chains used on a vehicle without the
proper amount of clearance can cause
damage to the brakes, suspension or
other vehicle parts. The area damaged by
the tire chains could cause you to lose
control of your vehicle and you or others
may be injured in a crash.
CAUTION: (Continued)
562

Scheduled Maintenance (cont’d)
Service MaintenanceIMaintenanceII
Inspect suspension and steering components.See footnote (b).•
Inspect engine cooling system.See footnote (c).•
Inspect wiper blades.See footnote (d).•
Inspect restraint system components.See footnote (e).•
Lubricate body components.See footnote (f).•
Check transmission uid level and add uid as needed.•
Inspect shields, vehicles with diesel engine or with GVWR above
10,000 lbs (4 536 kg) only.See footnote (n).•
620

Maintenance Footnotes
(Gasoline Engine)
This maintenance section applies to vehicles with
a gasoline engine. If your vehicle has a diesel
engine, see the maintenance schedule section in
the DURAMAX
®Diesel Engine Supplement.
†The U.S. Environmental Protection Agency or
the California Air Resources Board has determined
that the failure to perform this maintenance item
will not nullify the emission warranty or limit
recall liability prior to the completion of the
vehicle’s useful life. We, however, urge that all
recommended maintenance services be performed
at the indicated intervals and the maintenance
be recorded.
#Lubricate the front suspension, steering linkage,
transmission shift linkage, and parking brake
cable guides. Control arm ball joints require
lubrication but should not be lubricated unless
their temperature is 10°F (−12°C) or higher, or they
could be damaged. Vehicles used under severe
commercial operating conditions require lubrication
on a regular basis every 3,000 miles (5 000 km).(a)Visually inspect brake lines and hoses for
proper hook-up, binding, leaks, cracks, chang,
etc. Inspect disc brake pads for wear and rotors for
surface condition. Inspect drum brake
linings/shoes for wear or cracks. Inspect other
brake parts, including drums, wheel cylinders,
calipers, parking brake, etc.
(b)Visually inspect front and rear suspension and
steering system for damaged, loose or missing
parts, signs of wear or lack of lubrication. Inspect
power steering lines and hoses for proper
hook-up, binding, leaks, cracks, chang, etc.
Visually check constant velocity joints, rubber
boots, and axle seals for leaks.
(c)Visually inspect hoses and have them replaced
if they are cracked, swollen, or deteriorated.
Inspect all pipes, ttings and clamps; replace with
genuine GM parts as needed. To help ensure
proper operation, a pressure test of the cooling
system and pressure cap and cleaning the outside
of the radiator and air conditioning condenser is
recommended at least once a year.
(d)Visually inspect wiper blades for wear or
cracking. Replace wiper blades that appear worn
or damaged or that streak or miss areas of
the windshield.
623

In Canada, please call us at 1-800-263-3777
(English) or 1-800-263-7854 (French). Or, write:
General Motors of Canada Limited
Customer Communication Centre, CA1-163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
Service Publications Ordering
Information
Service Manuals
Service Manuals have the diagnosis and repair
information on engines, transmission, axle
suspension, brakes, electrical, steering, body, etc.
Transmission, Transaxle, Transfer
Case Unit Repair Manual
This manual provides information on unit repair
service procedures, adjustments, and
specications for GM transmissions, transaxles,
and transfer cases.
Service Bulletins
Service Bulletins give technical service information
needed to knowledgeably service General
Motors cars and trucks. Each bulletin contains
instructions to assist in the diagnosis and service
of your vehicle.
In Canada, the service bulletin reference number
can be obtained by contacting your General
Motors dealer or by calling 1-800-GM-DRIVE
(1-800-463-7483). This reference number is
needed to order the service bulletin from
Helm, Inc.
RETAIL SELL PRICE: $6.00 US + Processing Fee
657