2007 GMC SIERRA CLASSIC engine

Rear Axle
When to Check Lubricant
It is not necessary to regularly check rear axle
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.
All axle assemblies are lled by volume of uid
during production. They are not lled to reach
a certain level. When checking the uid level on
any axle, variations in the readings can be caused
by factory ll differences between the minimum
and the maximum uid volume. Also, if a vehicle
has just been driven before checking the uid
level, it may appear lower than normal because
uid has traveled out along the axle tubes and has
not drained back to the sump area. Therefore, a
reading taken ve minutes after the vehicle
has been driven will appear to have a lower uid
level than a vehicle that has been stationary
for an hour or two. Remember that the rear axle
assembly must be supported to get a true reading.
How to Check Lubricant
To get an accurate reading, the vehicle should be
on a level surface.
The proper level for the 1500 Series is from
5/8 inch to 1 5/8 inch (15 mm to 40 mm)
below the bottom of the ller plug hole.
The proper level for the 1500HD Series,
2500 Series and 2500HD Series with the
6.0L V8 engine (RPO LQ4) is from 0 to 1/2 inch
(0 to 13 mm) below the bottom of the ller
plug hole.
1500 Series Shown, 2500 Series Similar
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The proper level for the 2500HD with the
6.6L diesel engine (RPO LLY) or 8.1L V8
engine (RPO L18), and 3500 Series is from
0.6 to 0.8 inch (17 mm to 21 mm) below the
bottom of the ller plug hole.
Add only enough uid to reach the proper level.
What to Use
To determine what kind of lubricant to use see
Recommended Fluids and Lubricants on page 629.
Four-Wheel Drive
Lubricant checks in this section also apply to
these vehicles. There are two additional systems
that need lubrication.
Transfer Case
When to Check Lubricant
It is not necessary to regularly check transfer case
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
Manual Transfer Case
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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, located on the transfer case, 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.
When to Change Lubricant
Refer to the Maintenance Schedule to determine
how often to change the lubricant. See
Scheduled Maintenance (Gasoline Engine) on
page 617.
What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. SeeRecommended
Fluids and Lubricants on page 629.
Front Axle
When to Check Lubricant
It is not necessary to regularly check front axle
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.
Automatic Transfer Case
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Noise Control System
Tampering with Noise Control
System Prohibited
The following information relates to compliance
with federal noise emission standards for vehicles
with a Gross Vehicle Weight Rating (GVWR) of
more than 10,000 lbs (4 536 kg). The Maintenance
Schedule provides information on maintaining
the noise control system to minimize degradation
of the noise emission control system during
the life of your vehicle. The noise control system
warranty is given in your warranty booklet.
These standards apply only to vehicles sold in the
United States.Federal law prohibits the following acts or the
causing thereof:
1. The removal or rendering inoperative by
any person, other than for purposes of
maintenance, repair or replacement, of any
device or element of design incorporated into
any new vehicle for the purpose of noise
control, prior to its sale or delivery to the
ultimate purchaser or while it is in use; or
2. The use of the vehicle after such device or
element of design has been removed or
rendered inoperative by any person.
Among those acts presumed to constitute
tampering are the acts listed below.
Insulation:

Removal of the noise shields or any
underhood insulation.
Engine:

Removal or rendering engine speed governor,
if the vehicle has one, inoperative so as to
allow engine speed to exceed manufacturer
specications.
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Windshield Wiper Blade
Replacement
Windshield wiper blades should be inspected for
wear and cracking. SeeScheduled Maintenance
(Gasoline Engine) on page 617for more
information.
Replacement blades come in different types and
are removed in different ways. For proper type and
length, seeNormal Maintenance Replacement
Parts (Gasoline Engines) on page 632.To replace the windshield wiper blade assembly
do the following:
1. Lift the wiper arm away from the windshield.
2. Push the release lever (B) to disengage the
hook and push the wiper arm (A) out of the
blade (C).
3. Push the new wiper blade securely on the
wiper arm until you hear the release lever
click into place.
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(F) Tire Ply Material:The type of cord and
number of plies in the sidewall and under
the tread.
(G) Single Tire Maximum Load:Maximum load
that can be carried and the maximum pressure
needed to support that load when used as a
single. For information on recommended
tire pressure seeInation - Tire Pressure on
page 551andLoading Your Vehicle on page 409.
Tire Size
The following examples show the different parts of
a tire size.(A) Passenger (P-Metric) Tire:The United States
version of a metric tire sizing system. The letter P
as the rst character in the tire size means a
passenger vehicle tire engineered to standards set
by the U.S. Tire and Rim Association.
(A) Light Truck (LT-Metric) Tire:The United
States version of a metric tire sizing system. The
letters LT as the rst two characters in the tire
size means a light truck tire engineered to
standards set by the U.S. Tire and Rim
Association.
(B) Tire Width:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
Passenger (P-Metric) Tire
Light Truck (LT-Metric) Tire
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How to Check
Use a good quality pocket-type gage to check
tire pressure. You cannot tell if your tires are
properly inated simply by looking at them.
Radial tires may look properly inated even when
they’re underinated. Check the tire’s ination
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 rmly onto the valve to
get a pressure measurement. If the cold tire
ination pressure matches the recommended
pressure on the Tire and Loading Information
label, no further adjustment is necessary. If the
ination pressure is low, add air until you reach the
recommended amount.
If you overll 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
torque and wheel nut tightening information, see
Removing the Spare Tire and Tools on page 566.
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 553. Also seeScheduled Maintenance
(Gasoline Engine) on page 617.
{CAUTION:
If you operate your vehicle with a tire
that is badly underinated, the tire can
overheat. An overheated tire can lose air
suddenly or catch re. You or others
could be injured. Be sure all tires
(including the spare) are properly inated.
SeeInation - Tire Pressure on page 551, for
information on proper tire ination.
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Tire Inspection and Rotation
Tires should be rotated every 5,000 to 8,000 miles
(8 000 to 13 000 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.
SeeWhen It Is Time for New Tires on page 555
andWheel Replacement on page 560for
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/hoist shaft to tighten
the cable. SeeChanging a Flat Tire on page 564.
If your vehicle has dual rear wheels, also see
Dual Tire Operation on page 552.The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The
rst rotation is the most important. SeeScheduled
Maintenance (Gasoline Engine) on page 617.
If your vehicle has single rear wheels and the
tread design for your front tires is the same as your
rear tires, use the rotation pattern shown here
when rotating your tires.
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