GMC SIERRA 2021 Owner's Manual

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
380 Vehicle Care
If a Tire Goes Flat
It is unusual for a tire to blowout while
driving, especially if the tires are maintained
properly. If air goes out of a tire, it is much
more likely to leak out slowly. But if there
ever is a blowout, here are a few tips about
what to expect and what to do:
If a front tire fails, the flat tire creates 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 off the road,
if possible.
A rear blowout, particularly on a curve, acts
much like a skid and may require the same
correction as used in a skid. Stop pressing
the accelerator pedal and steer to straighten
the vehicle. It may be very bumpy and
noisy. Gently brake to a stop, well off the
road, if possible.{Warning
Driving on a flat tire will cause
permanent damage to the tire.
Re-inflating a tire after it has been driven
on while severely underinflated or flat
may cause a blowout and a serious crash.
Never attempt to re-inflate a tire that has
been driven on while severely
underinflated or flat. Have your dealer or
an authorized tire service center repair or
replace the flat tire as soon as possible.
{Warning
Lifting a vehicle and getting under it to
do maintenance or repairs is dangerous
without the appropriate safety equipment
and training. If a jack is provided with
the vehicle, it is designed only for
changing a flat tire. If it is used for
anything else, you or others could be
badly injured or killed if the vehicle slips
off the jack. If a jack is provided with the
vehicle, only use it for changing a
flat tire.If a tire goes flat, avoid further tire and
wheel damage by driving slowly to a level
place, well off the road, if possible. Turn on
the hazard warning flashers. See
Hazard
Warning Flashers 0142.
{Warning
Changing a tire can be dangerous. The
vehicle can slip off the jack and roll over
or fall causing injury or death. Find a
level place to change the tire. To help
prevent the vehicle from moving:
1. Set the parking brake firmly.
2. Shift the vehicle to P (Park).
3. For vehicles with four-wheel drive with an N (Neutral) transfer case
position, be sure the transfer case is
in a drive gear —not in N (Neutral).
4. Turn off the engine and do not restart while the vehicle is raised.
5. Do not allow passengers to remain in the vehicle.
6. Place wheel blocks, if equipped, on both sides of the tire at the opposite
corner of the tire being changed.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 381
When the vehicle has a flat tire (2), use the
following example as a guide to assist in the
placement of the wheel blocks (1),
if equipped.
1. Wheel Block (If Equipped)
2. Flat Tire
The following information explains how to
use the jack and change a tire.
Tire Changing
Removing the Spare Tire and Tools
1. Jack
2. Jack Knob
3. Tool Kit
4. Wing Nut Retaining Tool Kit
5. Wheel Blocks
6. Wing Nut Retaining Wheel Blocks
The equipment is under the second row
seats, if equipped, or behind the front row
seats on regular cab models.1. Turn the knob on the jack counterclockwise to lower the jack head
to release the jack from its holder. 2. Turn the wing nut counterclockwise to
remove the wheel blocks and the wheel
block retainer.
3. Turn the wing nut used to retain the storage bag and tools counterclockwise
to remove it.
Use the jack handle extensions and the
wheel wrench to remove the
underbody-mounted spare tire.1. Spare Tire (Valve Stem Pointed Down)
2. Tire/Wheel Retainer
3. Hoist Cable
4. Hoist Assembly
5. Hoist Shaft
6. Jack Handle Extensions

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
382 Vehicle Care
7. Wheel Wrench
8. Spare Tire Lock (If Equipped)
9. Hoist Shaft Access Hole
10. Hoist End of Extension Tool
1. Open the spare tire lock cover on thebumper and use the ignition key to
remove the spare tire lock (8). To remove
the spare tire lock, insert the ignition
key, turn, and pull straight out.
2. Assemble the wheel wrench (7) and thetwo jack handle extensions (6), as shown.
Spare Tire Cable (If Equipped)
3. If the vehicle is equipped with a spare tire cable disconnect the cable from the
attachment on the frame by unclipping
it from the frame attachment bracket.
4. Insert the hoist end (open end) (10) ofthe extension through the hole (9) in the
rear bumper.
Do not use the chiseled end of the wheel
wrench.
Be sure the hoist end of the
extension (10) connects to the hoist
shaft. The ribbed square end of the
extension is used to lower the spare tire.
5. Turn the wheel wrench 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.
6. Pull the spare tire out from under the vehicle.
7. Tilt the tire toward the vehicle withsome slack in the cable to access the
tire/wheel retainer.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 383
Tilt the retainer and pull it through the
center of the wheel along with the cable
and spring.
8. Put the spare tire near the flat tire.
9. If equipped with a spare tire cable remove the cable from the spare tire by
passing the clip through the looped end
of the cable.
Removing the Flat Tire and Installing the
Spare Tire
Use the following pictures and instructions
to remove the flat tire and raise the vehicle.
1. Jack
2. Wheel Blocks
3. Jack Handle
4. Jack Handle Extensions
5. Wheel Wrench
The tools you will be using include the
jack (1), the wheel blocks (2), the jack
handle (3), the jack handle extensions (4),
and the wheel wrench (5).
1. Do a safety check before proceeding. See If a Tire Goes Flat 0380.
2. If the vehicle has wheel nut caps, loosen
them by turning the wheel wrench
counterclockwise.
If the vehicle has a center cap with
wheel nut caps, the wheel nut caps are
designed to stay with the center cap
after they are loosened. Remove the
entire center cap.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
384 Vehicle Care
If the wheel has a smooth center cap,
concealing access to the wheel nuts,
place the chisel end of the wheel wrench
in the slot on the wheel, and gently pry
it out.
If the wheel’s center cap does not
conceal the wheel nuts, the center cap
may remain during wheel removal. If the
removed wheel is to be stowed in the
hoist, the cap needs to be detached from
the wheel. Access the wheel from the
back side, and use a jack handle
extension to push out the center cap.
3. Use the wheel wrench and turn itcounterclockwise to loosen the wheel
nuts. Do not remove the wheel nuts yet.
{Warning
To avoid personal injury and vehicle
damage, disable the power assist steps
before using a jack or placing an object
under the vehicle. See Power Assist Steps
0 30.
Front Position
4. If the flat tire is on the front of the vehicle, position the jack under the
bracket attached to the vehicle's frame,
behind the flat tire, as shown.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 385
Rear Position
5. If the flat tire is on the rear, position the jack under the rear axle about 5 cm
(2 in) inboard of the shock absorber
bracket.
{Warning
Getting under a vehicle when it is lifted
on a jack 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.
{Warning
Raising the 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.
{Warning
The jack has a feature to limit its travel
to prevent overextension. When the
height limit is reached, an increase in
resistance if felt when attempting to
raise the jack farther. Raising the jack
past the height limit can damage the jack
pin and cause the jack to lock into an
overextended position or not lower fully.
Do not attempt to force the jack higher
once the height limit is reached.
6. 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 fit under the
wheel well.7. Remove all the wheel nuts and take offthe flat tire.
{Warning
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
cause wheel nuts to become loose
over time. The wheel could come off
and cause a crash. When changing a
wheel, remove any rust or dirt from
places where the wheel attaches to
the vehicle. In an emergency, a cloth
or paper towel can be used; however,
use a scraper or wire brush later to
remove all rust or dirt.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
386 Vehicle Care
8. Remove any rust or dirt from the wheelbolts, mounting surfaces, and spare
wheel.
9. Install the spare tire.
{Warning
Never use oil or grease on bolts or nuts
because the nuts might come loose. The
vehicle's wheel could fall off, causing a
crash.
10. Put the wheel nuts back on with the rounded end of the nuts toward the
wheel. 11. Tighten each wheel nut by hand. Then
use the wheel wrench to tighten the
nuts until the wheel is held against
the hub.
12. Turn the wheel wrench counterclockwise to lower the vehicle. Lower the jack
completely.
{Warning
If wheel studs are damaged, they can
break. If all the studs on a wheel broke,
the wheel could come off and cause a
crash. If any stud is damaged because of
a loose-running wheel, it could be that all
of the studs are damaged. To be sure,
replace all studs on the wheel. If the stud
holes in a wheel have become larger, the
wheel could collapse in operation. Replace
any wheel if its stud holes have become
larger or distorted in any way. Inspect
hubs and hub‐piloted wheels for damage.
Because of loose running wheels, piloting
pad damage may occur and require
replacement of the entire hub, for proper
centering of the wheels. When replacing
studs, hubs, wheel nuts or wheels, be
sure to use GM original equipment parts.
{Warning
Wheel nuts that are improperly or
incorrectly tightened can cause the
wheels to become loose or come off. The
wheel nuts should be tightened with a
torque wrench to the proper torque
specification after replacing. Follow the
torque specification supplied by the
aftermarket manufacturer when using
accessory locking wheel nuts. See
Capacities and Specifications 0424 for
original equipment wheel nut torque
specifications.
Caution
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. See Capacities and
Specifications 0424 for the wheel nut
torque specification.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 387
13. Tighten the nuts firmly in a crisscrosssequence, as shown, by turning the
wheel wrench clockwise.
When reinstalling the regular wheel and tire,
also reinstall either the center cap,
or bolt-on hub cap, depending on what the
vehicle is equipped with. For center caps,
place the cap on the wheel and tap it into
place until it seats flush with the wheel. The
cap only goes on one way. Be sure to line
up the tab on the center cap with the
indentation on the wheel. For bolt-on hub
caps, align the plastic nut caps with the
wheel nuts and then tighten by hand. Then
use the wheel wrench to tighten.
Storing a Flat or Spare Tire and Tools
{Warning
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.
{Warning
Failure to follow these tire storage
instructions carefully could result in
personal injury or property damage if the
hoist cable fails or if the tire comes loose.
Make sure the tire is stored securely
before driving.
Caution
Storing an aluminum wheel with a flat
tire under your vehicle for an extended
period of time or with the valve stem
pointing up can damage the wheel.
Always stow the wheel with the valve
stem pointing down and have the wheel/
tire repaired as soon as possible.
Caution
The tire hoist can be damaged if there is
no tension on the cable when using it. To
have the necessary tension, the spare or
road tire and wheel assembly must be
installed on the tire hoist to use it.
{Warning
An improperly stored spare tire could
come loose and cause a crash. To avoid
personal injury or property damage,
always store the spare tire when the
vehicle is parked on a level surface.
Store the tire under the rear of the vehicle
in the spare tire carrier.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
388 Vehicle Care
1. Spare Tire (Valve Stem Pointed Down)
2. Tire/Wheel Retainer
3. Hoist Cable
4. Hoist Assembly
5. Hoist Shaft
6. Jack Handle Extensions
7. Wheel Wrench
8. Spare Tire Lock (If Equipped)
9. Hoist Shaft Access Hole
10. Hoist End of Extension Tool11. Spare Tire Cable (If Equipped)
1. If equipped with a spare tire cable,reinstall the cable to the spare wheel by
looping the cable around a wheel vent
window then pass the clip end of the cable through the looped end. The excess
cable wire should be on the valve stem
side of the spare tire.
2. Put the tire on the ground at the rear of the vehicle with the valve stem pointed
down, and to the rear.
3. Pull the cable and spring through the center of the wheel. Tilt the wheel
retainer plate down and through the
center wheel.
Make sure the retainer is fully seated
across the underside of the wheel.
4. Attach the wheel wrench (7) andextensions (6) together, as shown.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 389
Caution
Use of an air wrench or other power
tools with the hoist mechanism is not
recommended and could damage the
system. Use only the tools supplied with
the hoist mechanism.
5. Insert the hoist end (10) through thehole (9) in the rear bumper and onto the
hoist shaft.
Do not use the chiseled end of the wheel
wrench.
6. Raise the tire part way upward. Make sure the retainer is seated in the wheel
opening.
7. If equipped with a spare tire cable, orientthe cable by rotating the spare tire so
that the cable is by the frame
attachment location.
8. Raise the tire fully against the underside of the vehicle by turning the wheel
wrench clockwise until you hear two
clicks or feel it skip twice. You cannot
overtighten the cable.9. Make sure the tire is stored securely.Push, pull, and then try to turn the tire.
If the tire moves, use the wheel wrench
to tighten the cable.