wheel nut GMC SIERRA 1999 Owner's Manual

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4-58 Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you can tow in
AUTOMATIC OVERDRIVE (
). You may want to
shift the transmission to THIRD (3) or, if necessary, a
lower gear selection if the transmission shifts too often
(e.g., under heavy loads and/or hilly conditions).
If you have a manual transmission and you are towing a
trailer, it's better not to use FIFTH (5) gear. Just drive in
FOURTH (4) gear (or, as you need to, a lower gear).
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you turn
your engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) (or the
manual transmission out of gear and the parking brake
applied) for a few minutes before turning the engine off.
If you do get the overheat warning, see ªEngine
Overheatingº in the Index.
Parking on Hills
CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People can
be injured, and both your vehicle and the trailer
can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet for an automatic transmission, or into
gear for a manual transmission.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P) for an
automatic transmission, or REVERSE (R) for a
manual transmission.

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4-59
5. If you have a four-wheel-drive vehicle, be sure
the transfer case is in a drive gear and not in
NEUTRAL (N).
6. Release the regular brakes.
CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake firmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle won't move, even
when you're on fairly level ground, use the steps
that follow.
Always put the shift lever fully in PARK (P) with
the parking brake firmly set.
If the transfer case on four-wheel drive vehicles is
in NEUTRAL (N), your vehicle will be free to
roll, even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear
-- not in
NEUTRAL (N).
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

Start your engine;

Shift into a gear; and

Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system
and brake system. Each of these is covered in this
manual, and the Index will help you find them quickly.
If you're trailering, it's a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.

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5-24
With the UP marking on the ratchet facing you, rotate
the ratchet clockwise. That will lift the jack head a little.
If your vehicle has
wheel nut caps, use the
wheel wrench and ratchet
to remove them.
Turn the wheel wrench
counterclockwise,
with DOWN facing you,
to remove the
wheel nut caps.
Then take off the hub cap.
If the wheel also has a trim ring, use the wheel wrench
to pry along the edge and remove it.
If the wheel has a smooth center piece, place the wheel
wrench in the slot on the wheel and gently pry out.

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5-25 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. Position the jack under the vehicle. If the flat tire is
on the front of the vehicle, position the jack on the
frame behind the flat tire. If the flat tire is on the
rear, position the jack on the rear axle between the
spring and the shock absorber.
CAUTION:
Getting under a vehicle when it is jacked up is
dangerous. If the vehicle slips off the jack, you
could be badly injured or killed. Never get under
a vehicle when it is supported only by a jack.
CAUTION:
Raising your vehicle with the jack improperly
positioned can damage the vehicle and even make
the vehicle fall. To help avoid personal injury and
vehicle damage, be sure to fit the jack lift head
into the proper location before raising the vehicle.

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5-26
Front Position Rear Position
3. With UP on the ratchet facing you, raise the vehicle
by rotating 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.
4. Remove all the wheel
nuts and take off the
flat tire.
5. Remove any rust or dirt
from the wheel bolts,
mounting surfaces and
spare wheel.

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5-27
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.
6. Replace the wheel
nuts with the
rounded end of the
nuts toward the
wheel. Tighten
each wheel nut by
hand using the
wheel wrench until
the wheel is held
against the hub.

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5-28
Front Position Rear Position
7. Lower the vehicle by rotating the ratchet and wheel
wrench counterclockwise. Lower the jack completely.
8. Tighten the nuts
firmly in a crisscross
sequence as shown
by rotating 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 the
proper torque. See ªCapacities and
Specificationsº in the Index.

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5-29
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.
9. Put the wheel trim back on. For vehicles with plastic
wheel nut caps, tighten the caps until they are
finger
-tight, then tighten them an additional one-half
of a turn with the ratchet and wheel wrench.
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.
Store the flat tire where the spare tire was stored.

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5-31
2 and 4-Door Models
A. Nut
B. Jack
C. Jack Handle Extension
D. Wheel WrenchE. Jack and Tool
Storage Box
F. Ratchet
G. Jack Handle
H. Tool RetainerExtended Cab Models
A. Nut
B. Jack and Tool Cover
C. Jack Handle Extension
D. Tool Retainer
E. Jack and Tool
Storage BoxF. Ratchet
G. Wheel Wrench
H. Jack
I. Jack Handle

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5-32
Chassis Cab Models
A. Nut
B. Retainer
C. Jack Handle
Extension
D. Jack Handle Extension
E. Wheel WrenchF. Jack and Tool
Storage Box
G. Ratchet
H. Jack Handle
I. Tool Retainer
J. Jack
If You're Stuck: In Sand, Mud,
Ice or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you don't want to spin
your wheels too fast. The method known as ªrockingº
can help you get out when you're stuck, but you must
use caution.
CAUTION:
If you let your tires spin at high speed, they can
explode, and you or others could be injured. And,
the transmission or other parts of the vehicle can
overheat. That could cause an engine
compartment fire or other damage. When you're
stuck, spin the wheels as little as possible. Don't
spin the wheels above 35 mph (55 km/h) as shown
on the speedometer.