
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 205
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If a brake fade condition is detected, a DIC
warning message is displayed. Adjust brake
pedal use and shift to a lower transmission
gear to reduce braking.
If the brakes continue to fade to a severe
condition, additional DIC messages are
displayed. The brake system warning light
will illuminate, and the vehicle speed may
be limited. See Brake System Warning Light
0 124.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake. 2. Shift into P (Park) and then restart the
engine..If driving uphill when the vehicle
stalls, shift to R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle around.
If the hill is steep enough to stall the
vehicle, it is steep enough to cause it
to roll over.
.If you cannot make it up the hill,
back straight down the hill.
.Never back down a hill in N (Neutral)
using only the brake. The vehicle can
roll backward quickly and you could
lose control.
.If driving downhill when the vehicle
stalls, shift to a lower gear, release
the parking brake, and drive straight
down the hill.
3. If the vehicle cannot be restarted after stalling, set the parking brake, shift into
P (Park), and turn the vehicle off.
3.1. Leave the vehicle and seek help.
3.2. Stay clear of the path the vehicle would take if it rolled downhill.
{Warning
Getting out of the vehicle on the
downhill side when stopped across an
incline is dangerous. If the vehicle rolls
over, you could be crushed or killed.
Always get out on the uphill side of the
vehicle and stay well clear of the
rollover path.
Driving in Mud, Sand, Snow, or Ice
Use a low gear when driving in mud —the
deeper the mud, the lower the gear. Keep
the vehicle moving to avoid getting stuck.
Traction changes when driving on sand. On
loose sand, such as on beaches or sand
dunes, the tires tend to sink into the sand.
This affects steering, accelerating, and
braking. Drive at a reduced speed and avoid
sharp turns or abrupt maneuvers.
Traction is reduced on hard packed snow
and ice and it is easy to lose control. Reduce
vehicle speed when driving on hard packed
snow and ice.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
208 Driving and Operating
For Slippery Road Driving:
.Accelerate gently. Accelerating too quickly
causes the wheels to spin and makes the
surface under the tires slick.
.Turn on Traction Control. SeeTraction
Control/Electronic Stability Control 0236.
.The Antilock Brake System (ABS) improves
vehicle stability during hard stops, but
the brakes should be applied sooner than
when on dry pavement. See Antilock
Brake System (ABS) 0233.
.Allow greater following distance and
watch for slippery spots. Icy patches can
occur on otherwise clear roads in shaded
areas. The surface of a curve or an
overpass can remain icy when the
surrounding roads are clear. Avoid sudden
steering maneuvers and braking while
on ice.
.Turn off cruise control.
Cold Weather Mode
In very low temperatures, a cold weather
message may display on the Driver
Information Center (DIC). The engine speed,
transmission shift patterns, and cabin fan
speed may operate differently to enable the vehicle to warm up quicker. You can
manually override the cabin fan speed in
cold weather mode.
Blizzard Conditions
Stop the vehicle in a safe place and signal
for help. Stay with the vehicle unless there
is help nearby. If possible, use Roadside
Assistance. See
Roadside Assistance Program
0 408. To get help and keep everyone in
the vehicle safe:
.Turn on the hazard warning flashers.
.Tie a red cloth to an outside mirror.
{Warning
Snow can trap engine exhaust under the
vehicle. This may cause exhaust gases to
get inside. Engine exhaust contains
carbon monoxide (CO), which cannot be
seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in snow:
.Clear snow from the base of the
vehicle, especially any blocking the
exhaust pipe.
(Continued)
Warning (Continued)
.Open a window about 5 cm (2 in) on
the vehicle side that is away from the
wind, to bring in fresh air.
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to
circulate the air inside the vehicle and
set the fan speed to the highest
setting. See“Climate Control Systems.”
For more information about CO, see
Engine Exhaust 0222.
To save fuel, run the engine for short
periods to warm the vehicle and then shut
the engine off and partially close the
window. Moving about to keep warm also
helps.
If it takes time for help to arrive, when
running the engine, push the accelerator
pedal slightly so the engine runs faster than
the idle speed. This keeps the battery
charged to restart the vehicle and to signal
for help with the headlamps. Do this as
little as possible, to save fuel.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 209
If the Vehicle Is Stuck
Slowly and cautiously spin the wheels to
free the vehicle when stuck in sand, mud,
ice, or snow. See“Rocking the Vehicle to Get
It Out” later in this section.
The Traction Control/Electronic Stability
Control can often help to free a stuck
vehicle. See Traction Control/Electronic
Stability Control 0236. If TC/ESC cannot free
the vehicle, see “Rocking the Vehicle to Get
it Out” following.
{Warning
If the vehicle's tires spin at high speed,
they can explode, and you or others
could be injured. The vehicle can
overheat, causing an engine compartment
fire or other damage. Spin the wheels as
little as possible and avoid going above
56 km/h (35 mph).
For information about using tire chains on
the vehicle, see Tire Chains0363.
Rocking the Vehicle to Get It Out
Caution
Do not hold the steering wheel at full
rotation for more than 15 seconds and/or
at an elevated RPM. Damage may occur
to the power steering system and there
may be loss of power steering assist.
Turn the steering wheel left and right to
clear the area around the front wheels. Then
make sure the wheels are pointed straight
ahead. For four-wheel-drive vehicles, shift
into Four-Wheel Drive High. Turn the TCS
off. Shift back and forth between R (Reverse)
and a forward gear, spinning the wheels as
little as possible. To prevent transmission
wear, wait until the wheels stop spinning
before shifting gears. Slowly spinning the
wheels in the forward and reverse directions
causes a rocking motion that could free the
vehicle. If that does not get the vehicle out
after a few tries, it might need to be towed
out. See Transporting a Disabled Vehicle
0 379. Recovery hooks can be used, if the
vehicle has them.
Recovery Hooks
{Warning
Never pull on recovery hooks from the
side. The hooks could break and you and
others could be injured. When using
recovery hooks, always pull the vehicle
from the front.
Caution
Never use recovery hooks to tow the
vehicle. The vehicle could be damaged,
and the repairs would not be covered by
the vehicle warranty.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
224 Driving and Operating
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the shift
lever is in P (Park). You or someone else
could be seriously injured. Be sure the
transfer case is in a drive gear—2
m, 4m,
or 4
n— or set the parking brake before
placing the transfer case in N (Neutral).
See Four-Wheel Drive 0228.
R : Use this gear to back up.
Caution
Shifting to R (Reverse) while the vehicle is
moving forward could damage the
transmission. The repairs would not be
covered by the vehicle warranty. Shift to
R (Reverse) only after the vehicle is
stopped.
To rock the vehicle back and forth to get
out of snow, ice, or sand without damaging
the transmission, see If the Vehicle Is Stuck
0 209. N :
In this position, the engine does not
connect with the wheels. To restart the
engine when the vehicle is already moving,
use N (Neutral) only.
Also, use N (Neutral) when the vehicle is
being towed.
{Warning
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is firmly on
the brake pedal, the vehicle could move
very rapidly. You could lose control and
hit people or objects. Do not shift into a
drive gear while the engine is running at
high speed.
Caution
Shifting out of P (Park) or N (Neutral) with
the engine running at high speed may
damage the transmission. The repairs
would not be covered by the vehicle
warranty. Be sure the engine is not
running at high speed when shifting the
vehicle.
Caution
A transmission hot message may display
if the automatic transmission fluid is too
hot. Driving under this condition can
damage the vehicle. Stop and idle the
engine to cool the automatic
transmission fluid. This message clears
when the transmission fluid has cooled
sufficiently.
D : This position is for normal driving.
It provides the best fuel economy. If more
power is needed for passing, press the
accelerator pedal down.
.When going less than about 55 km/h
(35 mph), push the accelerator pedal
about halfway down.
.When going about 55 km/h (35 mph) or
more, push the accelerator all the
way down.
By doing this, the vehicle shifts down to
the next gear and has more power.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 225
Use D (Drive) and Tow/Haul Mode when
towing a trailer, carrying a heavy load,
driving on steep hills, or driving off-road.
Shift the transmission to a lower gear if the
transmission shifts too often.
Downshifting the transmission in slippery
road conditions could result in skidding. See
“Skidding”underLoss of Control 0202.
The vehicle has a shift stabilization feature
that adjusts the transmission shifting to the
current driving conditions in order to reduce
rapid upshifts and downshifts. This shift
stabilization feature is designed to
determine, before making an upshift, if the
engine is able to maintain vehicle speed by
analyzing things such as vehicle speed,
throttle position, and vehicle load. If the
shift stabilization feature determines that a
current vehicle speed cannot be maintained,
the transmission does not upshift and
instead holds the current gear. In some
cases, this could appear to be a delayed
shift, however the transmission is operating
normally. Grade Braking is available in all modes,
including Range Selection Mode. See
Manual
Mode 0226. Grade Braking assists in
maintaining desired vehicle speeds when
driving on downhill grades by using the
engine and transmission to slow the vehicle.
The transmission uses adaptive shift
controls. The adaptive shift control process
continually compares key shift parameters
to pre-programmed ideal shifts stored in the
transmission’s computer. The transmission
constantly makes adjustments to improve
vehicle performance according to how the
vehicle is being used, such as with a heavy
load or when the temperature changes.
During this adaptive shift control process,
shifting might feel different as the
transmission determines the best settings.
When temperatures are very cold, the
transmission's gear shifting may be delayed
to provide more stable shifts until the
engine warms up. Shifts could be more
noticeable with a cold transmission. This
difference in shifting is normal. L :
This position allows selection of a range
of gears appropriate for current driving
conditions. If equipped, see “Range Selection
Mode” underManual Mode 0226.
Caution
Spinning the tires or holding the vehicle
in one place on a hill using only the
accelerator pedal may damage the
transmission. The repair will not be
covered by the vehicle warranty. If the
vehicle is stuck, do not spin the tires.
When stopping on a hill, use the brakes
to hold the vehicle in place.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
236 Driving and Operating
HSA is available when the vehicle is facing
uphill in a forward gear, or when facing
downhill in R (Reverse). The vehicle must
come to a complete stop on a grade for HSA
to activate.
Ride Control Systems
Traction Control/Electronic
Stability Control
System Operation
The vehicle has a Traction Control System
(TCS) and StabiliTrak/Electronic Stability
Control (ESC) system. These systems help
limit wheel spin and assist the driver in
maintaining control, especially on slippery
road conditions.
TCS activates if it senses any of the drive
wheels are spinning or beginning to lose
traction. When this happens, TCS applies the
brakes to the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak/ESC activates when the vehicle
senses a difference between the intended
path and the direction the vehicle is actually
traveling. StabiliTrak/ESC selectively applies
braking pressure to any one of the vehicle
wheel brakes to assist the driver in keepingthe vehicle on the intended path. Trailer
Sway Control (TSC) is also on automatically
when the vehicle is started. See
Trailer Sway
Control (TSC) 0294.
If cruise control is being used and traction
control or StabiliTrak/ESC begins to limit
wheel spin, cruise control will disengage.
Cruise control may be turned back on when
road conditions allow.
Both systems come on automatically when
the vehicle is started and begins to move.
The systems may be heard or felt while
they are operating or while performing
diagnostic checks. This is normal and does
not mean there is a problem with the
vehicle.
It is recommended to leave both systems on
for normal driving conditions, but it may be
necessary to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow. See If the
Vehicle Is Stuck 0209 and“Turning the
Systems Off and On” later in this section.
When the transfer case (if equipped) is in
Four-Wheel Drive Low, the stability system
is automatically disabled,
gcomes on, and
the appropriate message will appear on the Driver Information Center (DIC). Both
traction control and StabiliTrak/ESC are
automatically disabled in this condition.
The indicator light for both systems is in the
instrument cluster. This light will:
.Flash when TCS is limiting wheel spin.
.Flash when StabiliTrak/ESC is activated.
.Turn on and stay on when either system
is not working.
If either system fails to turn on or to
activate, a message displays in the Driver
Information Center (DIC), and
dcomes on
and stays on to indicate that the system is
inactive and is not assisting the driver in
maintaining control. The vehicle is safe to
drive, but driving should be adjusted
accordingly.
If
dcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 239
standard/default mode. There is no
persistent indicator in the instrument cluster
for this mode.
6Snow/Ice Mode :Snow/Ice Mode
improves vehicle acceleration on snow and
ice covered roads. When active, Snow/Ice
Mode will adjust acceleration to optimize
traction on slippery surfaces. This can
compromise the acceleration on dry asphalt.
This feature is not intended for use when
the vehicle is stuck in sand, mud, ice, snow,
or gravel. If the vehicle becomes stuck, see If
the Vehicle Is Stuck 0209.
7Off-Road Mode : Use this mode for
off-road recreational driving. Off-Road Mode
should be used to improve driving at
moderate speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered roads. The
accelerator pedal is tuned for off-road use.
This mode modifies pedal mapping,
transmission shift pattern, Antilock Brake
System (ABS), StabiliTrak/Electronic Stability
Control (ESC), and Traction Control System
(TCS) performance.
For more information on off-road driving see
Off-Road Driving 0203.
_Tow/Haul Mode : Use this mode
when hauling heavy loads to provide
increased performance and vehicle control.
Tow/Haul Mode adjusts the transmission
shift pattern, trailer sway, and steering.
If the vehicle is turned off with Tow/Haul
Mode active and then restarted within four
hours or less, Tow/Haul will remain active.
Otherwise, the vehicle will start in
Normal Mode.
If the vehicle has a diesel engine, exhaust
braking is automatically activated when
Tow/Haul Mode is selected. It maintains
vehicle speed by automatically
implementing a shift pattern that uses the
engine and the transmission to slow the
vehicle. The system will command
downshifts and use the turbocharger on the
engine to reduce vehicle speed when the
brake is applied. The normal tow/haul shift
pattern will return once the vehicle is on a
low grade or when the accelerator pedal is
pressed.
While in the Electronic Range Select (ERS)
Mode, grade breaking is deactivated,
allowing the driver to select a range and
limiting the highest gear available. See
Manual Mode 0226. For more information on trailer weight
specifications, see
Towing Equipment 0284.
Locking Rear Axle
Vehicles with a locking rear axle can give
more traction on snow, mud, ice, sand,
or gravel. It works like a standard axle most
of the time, but when traction is low, this
feature will allow the rear wheel with the
most traction to move the vehicle.
Cruise Control
If equipped, cruise control allows the vehicle
to maintain a set speed of 40 km/h
(25 mph) or more without active
acceleration. Cruise control does not work at
speeds below about 40 km/h (25 mph).
{Warning
Cruise control can be dangerous where
you cannot drive safely at a steady
speed. Do not use cruise control on
winding roads or in heavy traffic.
Cruise control can be dangerous on
slippery roads. On such roads, fast
changes in tire traction can cause
(Continued)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Customer Information 409
In the U.S., anyone driving the vehicle is
covered. In Canada, a person driving the
vehicle without permission from the owner
is not covered.
Roadside Assistance is not a part of the New
Vehicle Limited Warranty. General Motors
North America and GMC reserve the right to
make any changes or discontinue the
Roadside Assistance program at any time
without notification.
General Motors North America and GMC
reserve the right to limit services or
payment to an owner or driver if they
decide the claims are made too often, or the
same type of claim is made many times.
Services Provided
.Emergency Fuel Delivery:Delivery of
enough fuel for the vehicle to get to the
nearest service station.
.Lock-Out Service: Service to unlock the
vehicle if you are locked out. A remote
unlock may be available if you have
OnStar. For security reasons, the driver
must present identification before this
service is given.
.Emergency Tow from a Public Road or
Highway: Tow to the nearest GMC dealer
for warranty service, or if the vehicle was
in a crash and cannot be driven.
Assistance is not given when the vehicle
is stuck in the sand, mud, or snow.
.Flat Tire Change: Service to change a flat
tire with the spare tire. The spare tire,
if equipped, must be in good condition
and properly inflated. It is the owner's
responsibility for the repair or
replacement of the tire if it is not covered
by the warranty.
.Battery Jump Start: Service to jump start
a dead battery.
.Trip Interruption Benefits and Assistance:
If your trip is interrupted due to a
warranty event, incidental expenses may
be reimbursed within the Powertrain
warranty period. Items considered are
reasonable and customary hotel, meals,
rental car, or a vehicle being delivered
back to the customer, up to 500 miles.
Services Not Included in Roadside
Assistance
.Impound towing caused by violation of
any laws
.Legal fines
.Mounting, dismounting, or changing of
snow tires, chains, or other traction
devices
Service is not provided if a vehicle is in an
area that is not accessible to the service
vehicle or is not a regularly traveled or
maintained public road, which includes ice
and winter roads. Off-road use is not
covered.
Services Specific to Canadian-Purchased
Vehicles
.Fuel Delivery: Reimbursement is up to
7 liters. Diesel fuel delivery may be
restricted. Propane and other fuels are
not provided through this service.
.Lock-Out Service: Vehicle registration is
required.