2021 GMC SIERRA four wheel drive

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
346 Vehicle Care
3. Turn the ignition on.
For vehicles not equipped with the Stop/
Start system: 1. Install the negative battery cable clamp to the negative battery post.
2. Tighten the negative battery cable nut.
3. Turn the ignition on.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
Refer to Maintenance Schedule 0409 to
determine when to check the lubricant.
1. Fill Plug
2. Drain Plug
To get an accurate reading, the vehicle
should be on a level surface.
If the level is below the bottom of the fill
plug (1) hole, located on the transfer case,
some lubricant will need to be added. Add
enough lubricant to raise the level to the
bottom of the fill plug (1) hole. Use care not
to overtighten the plug.
When to Change Lubricant
Refer to Maintenance Schedule 0409 to
determine how often to change the
lubricant.
What to Use
Refer to Recommended Fluids and Lubricants
0 418 to determine what kind of lubricant
to use.
Front Axle
When to Check Lubricant
It is not necessary to regularly check the
front axle fluid unless a leak is suspected or
an unusual noise is heard. A fluid loss could
indicate a problem. Have it inspected and
repaired. This service can be complex. See
your dealer. Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or drive axles and should be
replaced.
Rear Axle
When to Check Lubricant
It is not necessary to regularly check the
rear axle fluid unless a leak is suspected or
an unusual noise is heard. A fluid loss could
indicate a problem. Have it inspected and
repaired. This service can be complex. See
your dealer.
Do not directly power wash the transfer
case and/or front/rear axle output seals.
High pressure water can overcome the seals
and contaminate the fluid. Contaminated
fluid will decrease the life of the transfer
case and/or drive axles and should be
replaced.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 371
{Warning
Overinflating a tire could cause the tire
to rupture and you or others could be
injured. Do not exceed the maximum
pressure listed on the tire sidewall. See
Tire Sidewall Labeling0362 and
Vehicle Load Limits 0222.
If the tire is overinflated by more than
35 kPa (5 psi), the horn will sound multiple
times and the turn signal lamp will continue
to flash for several seconds after filling
stops. To release and correct the pressure,
while the turn signal lamp is still flashing,
briefly press the center of the valve stem.
When the recommended pressure is reached,
the horn sounds once.
If the turn signal lamp does not flash within
15 seconds after starting to inflate the tire,
the tire fill alert has not been activated or is
not working.
If the hazard warning flashers are on, the
tire fill alert visual feedback will not work
properly. The TPMS will not activate the tire fill alert
properly under the following conditions:.There is interference from an external
device or transmitter.
.The air pressure from the inflation device
is not sufficient to inflate the tire.
.There is a malfunction in the TPMS.
.There is a malfunction in the horn or turn
signal lamps.
.The identification code of the TPMS
sensor is not registered to the system.
.The battery of the TPMS sensor is low.
If the tire fill alert does not operate due to
TPMS interference, move the vehicle about
1 m (3 ft) back or forward and try again.
If the tire fill alert feature is not working,
use a tire pressure gauge.
TPMS Sensor Matching Process
Each TPMS sensor has a unique
identification code. The identification code
needs to be matched to a new tire/wheel
position after rotating the vehicle’s tires or
replacing one or more of the TPMS sensors.
Also, the TPMS sensor matching process
should be performed after replacing a spare
tire with a road tire containing the TPMS
sensor. The malfunction light and the DIC
message should go off at the next ignition cycle. The sensors are matched to the tire/
wheel positions, using a TPMS relearn tool,
in the following order: driver side front tire,
passenger side front tire, passenger side rear
tire, and driver side rear. See your dealer for
service or to purchase a relearn tool.
A TPMS relearn tool can also be purchased.
See Tire Pressure Monitor Sensor Activation
Tool at www.gmtoolsandequipment.com or
call 1-800-GM TOOLS (1-800-468-6657).
There are two minutes to match the first
tire/wheel position, and five minutes overall
to match all four tire/wheel positions. If it
takes longer, the matching process stops
and must be restarted.
The TPMS sensor matching process is:
1. Set the parking brake.
2. Turn the ignition on without starting the vehicle.
3. Uplevel DIC Only: Make sure the Tire Pressure info page option is turned on.
The info pages on the DIC can be turned
on and off through the Options menu.
See Driver Information Center (DIC) (Base
Level) 0124 or
Driver Information Center (DIC) (Midlevel
and Uplevel) 0125.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
372 Vehicle Care
4. If the vehicle has an uplevel DIC, use theDIC controls on the right side of the
steering wheel to scroll to the Tire
Pressure screen under the DIC info page.
If the vehicle has a base level DIC, use
the trip odometer reset stem to scroll to
the Tire Pressure screen.
5. If the vehicle has an uplevel DIC, press and hold the thumbwheel located in the
center of the DIC controls on the right
side of the steering wheel.
If the vehicle has a base level DIC, press
and hold the trip odometer reset stem
for about five seconds. A message asking
if the process should begin should
appear. Select yes and press the trip
odometer reset stem to confirm the
selection.
The horn sounds twice to signal the
receiver is in relearn mode and the TIRE
LEARNING ACTIVE message displays on
the DIC screen.
6. Start with the driver side front tire.
7. Place the relearn tool against the tire sidewall, near the valve stem. Then press
the button to activate the TPMS sensor.
A horn chirp confirms that the sensor
identification code has been matched to
this tire and wheel position. 8. Proceed to the passenger side front tire,
and repeat the procedure in Step 7.
9. Proceed to the passenger side rear tire, and repeat the procedure in Step 7.
10. Proceed to the driver side rear tire, and repeat the procedure in Step 7. The horn
sounds two times to indicate the sensor
identification code has been matched to
the driver side rear tire, and the TPMS
sensor matching process is no longer
active. The TIRE LEARNING ACTIVE
message on the DIC display screen
goes off.
11. Turn the vehicle off.
12. Set all four tires to the recommended air pressure level as indicated on the Tire
and Loading Information label.
Trailer Tire Pressure Monitoring
Operation
If equipped, the Trailer Tire Pressure
Monitoring System (TTPMS) is designed to
monitor the pressure of the trailer tires and
warn the driver when a low pressure
condition exists. TTPMS sensors for four tires
are provided. The system can accommodate
a trailer with up to six tires if additional sensors are purchased from the dealer. Also,
the system can be paired with up to five
individual trailers.
Prior to use, the vehicle must learn the
sensors by following the learning process.
See
Trailering App 0307.
Contact your trailer service center or tire
service center to have the pressure sensors
installed inside the trailer tires. The
technician should insert the sensor stem
through the hole in the trailer wheel. When
the sensor is correctly positioned, the nut on
the sensor stem should be tightened to
8Y (6 lb ft). When mounting the trailer
tire onto the trailer wheel be careful not to
damage the sensor.

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
390 Vehicle Care
If equipped with a spare tire cable,
reattach the clip to the frame
attachment bracket. Note that there may
be slack in the cable.
Repeat this tightness check procedure
when checking the spare tire pressure
according to the scheduled maintenance
information or any time the spare tire is
handled due to service of other
components.
Correctly Stored
Incorrectly Stored
10. Reinstall the spare tire lock, if the vehicle has one.
Return the jack and tools to their original
location in the vehicle. See “Removing the
Spare Tire and Tools.”
Full-Size Spare Tire
If this vehicle came with a full-size spare
tire, it was fully inflated when new,
however, it can lose air over time. Check the
inflation pressure regularly. See Tire Pressure
0 367 and
Vehicle Load Limits 0222 for information
regarding proper tire inflation and loading
the vehicle. For instructions on how to
remove, install, or store a spare tire, see Tire
Changing 0381.
If equipped with a temporary use full-size
spare tire, it is indicated on the tire sidewall.
See Tire Sidewall Labeling 0362. This spare
tire should not be driven on over 112 km/h
(70 mph), or 88 km/h (55 mph) when
pulling a trailer, at the proper inflation
pressure. Repair and replace the road tire as
soon as it is convenient, and stow the spare
tire for future use.
Caution
If the vehicle has four-wheel drive and a
different size spare tire is installed, do
not drive in four-wheel drive until the flat
tire is repaired and/or replaced. The
vehicle could be damaged and the repairs
(Continued)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 391
Caution (Continued)
would not be covered by the warranty.
Never use four-wheel drive when a
different size spare tire is installed on the
vehicle.
The vehicle may have a different size spare
tire than the road tires originally installed
on the vehicle. This spare tire was developed
for use on this vehicle, so it is all right to
drive on it. If the vehicle has four-wheel
drive and a different size spare tire is
installed, drive only in two-wheel drive.
After installing the spare tire on the vehicle,
stop as soon as possible and check that the
spare is correctly inflated. The spare tire is
made to perform well at speeds up to
112 km/h (70 MPH) at the recommended
inflation pressure, so you can finish
your trip.
Have the damaged or flat road tire repaired
or replaced and installed back onto the
vehicle as soon as possible so the spare tire
will be available in case it is needed again.
Do not mix tires and wheels of difference
sizes, because they will not fit. Keep the
spare tire and its wheel together. If the vehicle has a spare tire that does not
match the original road tires and wheels in
size and type, do not include the spare in
the tire rotation.
Jump Starting
Jump Starting - North America
For more information about the vehicle
battery, see
Battery - North America 0343.
If the vehicle's battery (or batteries) has run
down, you may want to use another vehicle
and some jumper cables to start your
vehicle. Be sure to use the following steps
to do it safely.
{Warning
WARNING: Battery posts, terminals, and
related accessories contain lead and lead
compounds, chemicals known to the
State of California to cause cancer and
birth defects or other reproductive harm.
Batteries also contain other chemicals
known to the State of California to cause
cancer. WASH HANDS AFTER HANDLING.
(Continued)
Warning (Continued)
For more information go to
www.P65Warnings.ca.gov/
passenger-vehicle.
See California Proposition 65 Warning 0322
and the back cover.
{Warning
Batteries can hurt you. They can be
dangerous because:
.They contain acid that can burn you.
.They contain gas that can explode or
ignite.
.They contain enough electricity to
burn you.
If you do not follow these steps exactly,
some or all of these things can hurt you.
Caution
Ignoring these steps could result in costly
damage to the vehicle that would not be
covered by the vehicle warranty. Trying
(Continued)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
392 Vehicle Care
Caution (Continued)
to start the vehicle by pushing or pulling
it will not work, and it could damage the
vehicle.
1. Good Battery Positive Terminal
2. Good Battery Negative Terminal
3. Discharged Battery Remote NegativeTerminal
4. Discharged Battery Remote Positive Terminal
The jump start positive post (1) and negative
post (2) are on the battery of the vehicle
providing the jump start. The jump start positive post (4) and the
negative grounding point (3) for the
discharged battery are on the passenger side
of the vehicle.
The positive jump start connection for the
discharged battery is under a cover. Slide
the cover to expose the terminal.
1. Check the other vehicle. It must have a 12-volt battery with a negative ground
system.
Caution
If the other vehicle does not have a
12-volt system with a negative ground,
both vehicles can be damaged. Only use
a vehicle that has a 12-volt system with a
negative ground for jump starting.
2. If you have a vehicle with a diesel engine with two batteries, you should
know before you begin that, especially in
cold weather, you may not be able to
get enough power from a single battery
in another vehicle to start your diesel
engine. If your vehicle has more than
one battery, using the battery that is
closer to the starter will reduce electrical resistance. This is located on the
passenger side, in the rear of the engine
compartment.
3. Get the vehicles close enough so the jumper cables can reach, but be sure the
vehicles are not touching each other.
If they are, it could cause an unwanted
ground connection. You would not be
able to start your vehicle, and the bad
grounding could damage the electrical
systems.
To avoid the possibility of the vehicles
rolling, set the parking brake firmly on
both vehicles involved in the jump start
procedure. Put the automatic
transmission in P (Park) before setting
the parking brake. If you have a
four-wheel-drive vehicle, be sure the
transfer case is in a drive gear, not in
N (Neutral).
Caution
If any accessories are left on or plugged
in during the jump starting procedure,
they could be damaged. The repairs
would not be covered by the vehicle
warranty. Whenever possible, turn off or
unplug all accessories on either vehicle
when jump starting.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Vehicle Care 395
Recreational Vehicle Towing
Recreational vehicle towing means towing
the vehicle behind another vehicle, such as a
motor home. The two most common types
of recreational vehicle towing are dinghy
and dolly towing. Dinghy towing is towing
the vehicle with all four wheels on the
ground. Dolly towing is towing the vehicle
with two wheels on the ground and two
wheels on a dolly.
Here are some important things to consider
before recreational vehicle towing:
.Before towing the vehicle, become
familiar with the local laws that apply to
recreational vehicle towing. These laws
may vary by region.
.The towing capacity of the towing
vehicle. Read the tow vehicle
manufacturer's recommendations.
.How far the vehicle can be towed. Some
vehicles have restrictions on how far and
how long the vehicle can be towed.
.Whether the vehicle has the proper
towing equipment. See your dealer or
trailering professional for additional
advice and equipment recommendations.
.Whether the vehicle is ready to be towed.
Just as preparing the vehicle for a long
trip, make sure the vehicle is prepared to
be towed.
Follow the tow vehicle manufacturer’s
instructions. See your dealer or trailering
professional for additional advice and
equipment recommendations.
Caution
Use of a shield mounted in front of the
vehicle grille could restrict airflow and
cause damage to the transmission. The
repairs would not be covered by the
vehicle warranty. If using a shield, only
use one that attaches to the towing
vehicle.
Dinghy Towing (Two-Wheel-Drive
Vehicles and Vehicles with a
Single-Speed Transfer Case)
Caution
If a vehicle with two-wheel drive or a
single-speed transfer case is towed with
all four wheels on the ground, the
drivetrain components could be damaged.
The repairs would not be covered by the
vehicle warranty.
Two-wheel-drive vehicles and vehicles with a
single-speed transfer case should not be
towed with all four wheels on the ground.