wheel GMC YUKON 1999 Workshop Manual

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5-8
Towing Your Vehicle
CAUTION:
To help avoid serious personal injury to you
or others:

Never let passengers ride in a vehicle that is
being towed.

Never tow faster than safe or posted speeds.

Never tow with damaged parts not
fully secured.

Never get under your vehicle after it has
been lifted by the tow truck.

Always secure the vehicle on each side with
separate safety chains when towing it.

Use only the correct hooks.
NOTICE:
Use the proper towing equipment to avoid
damage to the bumper, fascia or fog lamp areas
of the vehicle.
With current trends in automotive styles and design, it is
essential that the correct towing equipment is used to
tow a vehicle. Your vehicle can be towed with wheel
-lift
equipment or car carrier equipment. The transfer case
must be placed in NEUTRAL (N). The towing limits for
wheel lift equipment are:

Front Towing
-- 55 mph (88 km/h) or legal speed
limit and distance is unlimited

Rear Towing
-- 35 mph (55 km/h) for 50 miles
(80 km).
Consult your dealer or a professional towing service if
you need to have your vehicle towed. See ªRoadside
Assistanceº in the Index.

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Engine Fan Noise
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 disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
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'd 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.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.

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Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your hazard
warning flashers.
CAUTION:
Changing a tire can cause an injury. The vehicle
can slip off the jack and roll over you or other
people. You and they could be badly injured.
Find a level place to change your tire. To help
prevent the vehicle from moving:
1. Set the parking brake firmly.
2. Put the shift lever in PARK (P).
3. If you have a four
-wheel-drive vehicle,
be sure the transfer case is in a drive
gear
-- not in NEUTRAL (N).
4. Turn off the engine.
To be even more certain the vehicle won't move,
you can put blocks at the front and rear of the
tire farthest away from the one being changed.
That would be the tire on the other side of the
vehicle, at the opposite end.
The following steps will tell you how to use the jack and
change a tire.

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A. Hoist Assembly
B. Hoist Shaft
C. Ratchet
D. Jack HandleE. Retainer
F. Valve Stem,
Pointed Down
G. Spare TireFollow these instructions to lower the spare tire:
1. One side of the ratchet has an UP marking. The other
side has a DOWN marking. Assemble the ratchet
to the hook near the end of the jack handle
(as illustrated) with the DOWN marking facing
you. Insert the other end through the hole in the
rear bumper and into the hoist shaft.
2. Turn the ratchet counterclockwise to lower the spare
tire to the ground. Continue to turn the ratchet
until the spare tire can be pulled out from under
the vehicle.
3. When the tire has been lowered, tilt the retainer at
the end of the cable so it can be pulled up through
the wheel opening.
4. Put the spare tire near the flat tire.

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5-22
The tools you'll be using include the jack (A), the jack
handle extension (B), the jack handle (C), the wheel
wrench (D) and the ratchet (E).
The jack handle extension is used if the flat tire is on the
rear of the vehicle.Attach the jack handle (and jack handle extension, if
needed) to the jack.

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5-24
To access the lug nuts, place the wheel wrench in the
slot on the wheel and gently pry off the center piece to
remove it.
Removing the Flat Tire and Installing the
Spare Tire
1. Use the ratchet and wheel wrench to loosen
all the wheel nuts. Turn the wheel wrench
counterclockwise, with DOWN facing you, to loosen
the wheel nuts. Don't remove the wheel nuts yet.
2. If the flat tire is on the rear of the vehicle, put the
jack handle extension on the jack handle.

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Front Position Rear Position
4. With UP on the ratchet facing you, raise the vehicle
by turning the ratchet and wheel wrench clockwise.
Raise the vehicle far enough off the ground so there
is enough room for the spare tire to fit.
5. Remove all the wheel
nuts and take off the
flat tire.
6. Remove any rust or dirt
from the wheel bolts,
mounting surfaces and
spare wheel.

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CAUTION:
Rust or dirt on the wheel, or on the parts to
which it is fastened, can make the wheel nuts
become loose after a time. The wheel could come
off and cause an accident. When you change a
wheel, remove any rust or dirt from the 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 you need to, to get all the rust or
dirt off.
CAUTION:
Never use oil or grease on studs or nuts. If you
do, the nuts might come loose. Your wheel could
fall off, causing a serious accident.
7. Replace the wheel nuts
with the rounded end of
the nuts toward the
wheel. Tighten each
wheel nut by hand with
the wheel wrench until
the wheel is held against
the hub.

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Front Position Rear Position
8. Lower the vehicle by turning the ratchet and wheel
wrench counterclockwise. Lower the jack completely.
9. Tighten each wheel nut by turning the wheel
wrench clockwise.

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10. Tighten the nuts firmly
in a crisscross
sequence as shown.
Turn the wheel
wrench clockwise.
CAUTION:
Incorrect wheel nuts or improperly tightened
wheel nuts can cause the wheel to become loose
and even come off. This could lead to an accident.
Be sure to use the correct wheel nuts. If you have
to replace them, be sure to get new GM original
equipment wheel nuts.
Stop somewhere as soon as you can and have the
nuts tightened with a torque wrench to
140 lb
-ft (190 N´m)
NOTICE:
Improperly tightened wheel nuts can lead to
brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specification.