2007 GMC SIERRA tow

Engine Fan Noise
If your vehicle has a clutched engine cooling fan,
when the clutch is engaged, the fan spins
faster to provide more air to cool the engine. In
most everyday driving conditions, the fan is
spinning slower and the clutch is not fully engaged.
This improves fuel economy and reduces fan
noise. Under heavy vehicle loading, trailer towing,
and/or high outside temperatures, the fan speed
increases as the clutch more fully engages, so you
may hear an increase in fan noise. This is
normal and should not be mistaken as the
transmission slipping or making extra shifts. It is
merely the cooling system functioning properly.
The fan will slow down when additional cooling is
not required and the clutch disengages.You may also hear this fan noise when you start
the engine. It will go away as the fan clutch
partially disengages.
If your vehicle has electric cooling fans, you may
hear the fans spinning at low speed during most
everyday driving. The fans may turn off if no cooling
is required. Under heavy vehicle loading, trailer
towing, and/or high outside temperatures, or if you
are operating your air conditioning system, the fans
may change to high speed and you may hear an
increase in fan noise. This is normal and indicates
that the cooling system is functioning properly. The
fans will change to low speed when additional
cooling is no longer required.
525

If your vehicle has dual
rear wheels and the
tread design for the front
tires is different from
the dual rear tires,
always use the correct
rotation pattern
shown here when
rotating your tires.
The dual tires are rotated as a pair, and the inside
rear tires become the outside rear tires.
When you install dual wheels, be sure the vent
holes in the inner and outer wheels on each side
are lined up.
After the tires have been rotated, adjust the front
and rear ination pressures as shown on the
Tire and Loading Information label. SeeLoading
Your Vehicle on page 425.Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and Specications on page 616.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When
you change a wheel, remove any rust or
dirt from places where the wheel attaches
to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this;
but be sure to use a scraper or wire brush
later, if needed, to get all the rust or dirt
off. SeeChanging a Flat Tire on page 576.
567

If a Tire Goes Flat
It is unusual for a tire to blowout while you are
driving, especially if you maintain your vehicle’s
tires properly. If air goes out of a tire, it is
much more likely to leak out slowly. But if you
should ever have a blowout, here are a few tips
about what to expect and what to do:
If a front tire fails, the at tire will create a drag
that pulls the vehicle toward that side. Take your
foot off the accelerator pedal and grip the
steering wheel rmly. Steer to maintain lane
position, and then gently brake to a stop well out
of the traffic lane.
A rear blowout, particularly on a curve, acts much
like a skid and may require the same correction
you would use in a skid. In any rear blowout
remove your foot from the accelerator pedal. Get
the vehicle under control by steering the way
you want the vehicle to go. It may be very bumpy
and noisy, but you can still steer. Gently brake
to a stop, well off the road if possible.{CAUTION:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous
without the appropriate safety equipment
and training. The jack provided with your
vehicle is designed only for changing a
at tire. If it is used for anything else, you
or others could be badly injured or killed
if the vehicle slips off the jack. Use the
jack provided with your vehicle only for
changing a at tire.
If a tire goes at, the next part shows how to use
the jacking equipment to change a at tire safely.
Changing a Flat Tire
If a tire goes at, avoid further tire and wheel
damage by driving slowly to a level place. Turn on
your hazard warning ashers. SeeHazard
Warning Flashers on page 211for more
information.
576

3. Insert the hoist end
(open end) (F) of the
extension through
the hole (G) in
the rear bumper.
Be sure the hoist end of the extension (F)
connects to the hoist shaft (E). The ribbed
square end of the extension is used to lower
the spare tire.
4. Turn the wheel wrench (H) counterclockwise
to lower the spare tire to the ground. Continue
to turn 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. SeeSecondary Latch
System on page 589.5. Use the wheel
wrench hook which
allows you to
pull the hoist cable
towards you to
assist in reaching
the spare tire.
6. Tilt the retainer (D)
at the end of the
cable (C) when the
tire has been
lowered, so it can
be pulled up through
the wheel opening.
7. Put the spare tire near the at tire.
581

4. Turn the wheel wrench clockwise to raise the
vehicle. Raise the vehicle far enough off the
ground so there is enough room for the spare
tire to t under the wheel well.
5. Remove all the
wheel nuts and take
off the at tire.
{CAUTION:
Rust or dirt on the wheel, or on the parts
to which it is fastened, can make the
wheel nuts become loose after time. The
wheel could come off and cause an
accident. When changing a wheel, remove
any rust or dirt from the places where the
wheel attaches to the vehicle. In an
emergency, a cloth or a paper towel can
be used to do this; but be sure to use a
scraper or wire brush later, if needed, to
get all the rust or dirt off.
586

6. Remove any rust or
dirt from the wheel
bolts, mounting
surfaces, and spare
wheel.
7. Install the spare tire.
{CAUTION:
Never use oil or grease on studs or nuts.
Because the nuts might come loose. The
vehicle’s wheel could fall off, causing a
serious accident.
8. Put the wheel nuts back on with the rounded
end of the nuts toward the wheel.
9. Tighten each wheel nut by hand. Then use
the wheel wrench to tighten the nuts until the
wheel is held against the hub.
10. Turn the wheel wrench counterclockwise to
lower the vehicle. Lower the jack completely.
587

5. If the spare tire does not lower, turn the wheel
wrench counterclockwise until approximately
6 inches (15 cm) of cable is exposed.
6. Stand the wheel blocks on their shortest ends,
with the backs facing each other.
7. Place the bottom
edge of the jack (A)
on the wheel
blocks (B),
separating them so
that the jack is
balanced securely.
8. Attach the jack handle, extension, and wheel
wrench to the jack and place it (with the
wheel blocks) under the vehicle toward the
front of the rear bumper.
590

15. Tilt the tire retainer
at the end of the
cable and pull
it through the wheel
opening. Pull the
tire out from
under the vehicle.
16. Turn the wheel wrench in the hoist shaft hole
in the bumper clockwise to raise the cable
back up if the cable is hanging under
the vehicle.
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 replaced.
To continue changing the at tire, seeRemoving
the Flat Tire and Installing the Spare Tire on
page 582.Storing a Flat or Spare Tire and
Tools
{CAUTION:
Storing a jack, a tire, or other equipment
in the passenger compartment of the
vehicle could cause injury. In a sudden
stop or collision, loose equipment could
strike someone. Store all these in the
proper place.
Notice:Storing an aluminum wheel with a at
tire under your vehicle for an extended
period of time or with the valve stem pointing
up may damage the wheel. Always stow
the wheel with the valve stem pointing down
and have the wheel/tire repaired as soon
as possible.
Store the tire under the rear of the vehicle in the
spare tire carrier.
592