2013 GMC SIERRA Traction

Black plate (14,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-14 Driving and Operating
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 Your Vehicle to Get It
Out”later in this section.
If the vehicle has a traction system,
it can often help to free a stuck
vehicle. Refer to the vehicle's
traction system in the Index. If stuck
too severely for the traction system
to free the vehicle, turn the traction
system off and use the rocking
method.
{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
Chains on page 10‑70.
Rocking Your Vehicle to Get
It Out
Turn the steering wheel left and
right to clear the area around the
front wheels. For four-wheel-drive
vehicles, shift into Four-Wheel High.
For vehicles with StabiliTrak
®, turn
the traction control part of the
system 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.
Release the accelerator pedal while
shifting, and press lightly on the
accelerator pedal when the
transmission is in gear. 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. Recovery
hooks can be used, if the vehicle
has them. If the vehicle does need
to be towed out, see
Towing the
Vehicle on page 10‑87.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.

Black plate (37,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-37
Low Traction Mode
If the vehicle has the Allison
Transmission, a 4-Speed automatic
transmission, or the Hydra-Matic
6-Speed Automatic Transmission
with the 6.0L engine, it has a Low
Traction Mode that assists in vehicle
acceleration when road conditions
are slippery, such as with ice or
snow. While the vehicle is at a stop,
select the second gear range using
Range Selection Mode. This will
limit torque to the wheels helping to
prevent the tires from spinning.
Tow/Haul Mode
4-Speed Automatic Transmission
6-Speed Automatic Transmission
Vehicles with an automatic
transmission have a Tow/Haul
Mode. The Tow/Haul Mode adjusts
the transmission shift pattern to
reduce shift cycling, providing
increased performance, vehicle
control, and transmission cooling
when driving down steep hills or
Mountain grades, towing, or hauling
heavy loads.
The selector button is located on the
end of the shift lever. Turn the Tow/
Haul Mode on and off by pressing
the button. When the Tow/Haul
Mode is enabled, a light on the
instrument panel cluster will
come on. See
Tow/Haul Mode Light on
page 5‑25 andHill and Mountain
Roads on page 9‑11 for more
information.
Also see “Tow/Haul Mode” under
Towing Equipment on page 9‑89 for
more information.
Tow/Haul Mode Grade Braking
(6-Speed Automatic
Transmission)
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See “Tow/Haul Mode” listed
previously and Manual Mode on
page 9‑36. Tow/Haul Mode Grade
Braking assists in maintaining
desired vehicle speeds when driving
on downhill grades by using the
engine and transmission to slow the
vehicle.

Black plate (38,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-38 Driving and Operating
On vehicles with a gasoline engine,
to disable or enable Tow/Haul
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
three seconds. A DIC message will
be displayed. SeeTransmission
Messages on page 5‑44.
On vehicles with a diesel engine.
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment on
page 9‑89 for more information.
For other forms of grade braking,
see Automatic Transmission on
page 9‑32 andCruise Control on
page 9‑56.Drive Systems
Four-Wheel Drive
If the vehicle has Four-Wheel Drive,
you can send the engine's driving
power to all four wheels for extra
traction. To get the most satisfaction
out of Four-Wheel Drive, you must
be familiar with its operation. Read
the following before using
Four-Wheel Drive. See the
appropriate text for the transfer case
in the vehicle.
Notice: Driving on clean, dry
pavement in Four-Wheel Drive
High or Four-Wheel Drive Low for
an extended period of time may
cause premature wear on the
vehicle's powertrain. Do not drive
on clean, dry pavement in
Four-Wheel Drive High or
Four-Wheel Drive Low for
extended periods of time.
While driving on clean dry pavement
and during tight turns, you may
experience vibration in the steering
system. If the vehicle has StabiliTrak
®,
shifting into Four-Wheel Drive Low
will turn Traction Control and
StabiliTrak off. See StabiliTrak
®
System on page 9‑53.
Front Axle
The front axle engages and
disengages automatically when you
shift the transfer case. Some delay
for the axle to engage or disengage
is normal.
Manual Transfer Case

Black plate (40,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-40 Driving and Operating
If the vehicle has StabiliTrak®,
shifting into Four-Wheel Drive Low
will turn Traction Control and
StabiliTrak off. See StabiliTrak
®
System on page 9‑53.
A parking brake symbol is located
next to the N (Neutral) symbol as a
reminder to set the parking brake
before shifting the transfer case into
N (Neutral).
{WARNING
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
(Continued)
WARNING (Continued)
before placing the transfer case in
N (Neutral). SeeParking Brake on
page 9‑51.
N (Neutral): Shift to this setting
only when the vehicle needs to be
towed. See Recreational Vehicle
Towing on page 10‑87 orTowing the
Vehicle on page 10‑87.
2
m(Two-Wheel Drive High): This
setting is used for driving in most
street and highway situations.
The front axle is not engaged in
two-wheel drive. This setting also
provides the best fuel economy.
4
m(Four-Wheel Drive High): Use
this setting when you need extra
traction, such as on snowy or icy
roads or in most off-road situations.
This setting also engages the front
axle to help drive your vehicle. This
is the best setting to use when
plowing snow. You can shift from Two-Wheel Drive
High to Four-Wheel Drive High or
Four-Wheel Drive High to
Two-Wheel Drive High while the
vehicle is moving. In extremely cold
weather, it may be necessary to
stop or slow the vehicle to shift into
Four-Wheel Drive High.
When Using the Manual
Transfer Case
.Shifts into or out of Four-Wheel
Drive Low or N (Neutral) should
be made using quick motions to
avoid excessive gear grinding.
Shifting slowly may make it more
difficult to shift.
.You may notice that it is harder
to shift when the vehicle is cold.
After the vehicle warms up the
shifting will return to normal.
.While in Four-Wheel High or
Four-Wheel Drive Low you
may experience reduced fuel
economy.

Black plate (43,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-43
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m 4m4n N
Normal YES Severe YES
Extreme YES
Vehicle in Tow* YES
*See Recreational Vehicle Towing on page 10‑87 orTowing the Vehicle on
page 10‑87.
You can choose among four driving
settings:
Indicator lights in the dial show
which setting you are in. The
indicator lights will come on briefly
when you turn on the ignition and
one will stay on. If the lights do not
come on, you should take the
vehicle to your dealer for service. An indicator light flashes while
shifting the transfer case and
remains illuminated when the shift is
complete. If for some reason the
transfer case cannot make a
requested shift, it will return to the
last chosen setting.
2
m(Two-Wheel Drive High):
This
setting is used for driving in most
street and highway situations. The
front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy. 4
m(Four-Wheel Drive High):
Use
the Four-Wheel Drive High position
when extra traction is needed, such
as on snowy or icy roads or in most
off-road situations. This setting also
engages the front axle to help drive
the vehicle. This is the best setting
to use when plowing snow.
4
n(Four-Wheel Drive Low): This
setting also engages the front axle
and delivers extra torque. You may
never need this setting. It sends
maximum power to all four wheels.
You might choose Four-Wheel Drive
Low while driving off-road in deep
sand, deep mud, deep snow, and
while climbing or descending steep
hills.
If the vehicle has StabiliTrak
®,
shifting into Four-Wheel Drive Low
will turn Traction Control and
StabiliTrak off. See StabiliTrak
®
System on page 9‑53.

Black plate (47,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-47
You can choose among five driving
settings:
Indicator lights in the dial show
which setting you are in. The
indicator lights will come on briefly
when you turn on the ignition and
one will stay on. If the lights do not
come on, you should take the
vehicle to your dealer for service.
An indicator light will flash while
shifting the transfer case. It will
remain illuminated when the shift is
complete. If for some reason the
transfer case cannot make a
requested shift, it will return to the
last chosen setting.
2
m(Two-Wheel Drive High):This
setting is used for driving in most
street and highway situations. The
front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy.
AUTO (Automatic Four-Wheel
Drive): This setting is ideal for use
when road surface traction
conditions are variable. When
driving the vehicle in AUTO, the front axle is engaged, but the
vehicle's power is sent only to the
front and rear wheels automatically
based on driving conditions. Driving
in this mode results in slightly lower
fuel economy than Two-Wheel
Drive High.
4
m(Four-Wheel Drive High):
Use
the Four-Wheel Drive High position
when extra traction is needed, such
as on snowy or icy roads or in most
off-road situations. This setting also
engages the front axle to help drive
the vehicle. This is the best setting
to use when plowing snow.
4
n(Four-Wheel Drive Low): This
setting also engages the front axle
and delivers extra torque. You may
never need this setting. It sends
maximum power to all four wheels.
You might choose Four-Wheel Drive
Low if you are driving off-road in
deep sand, deep mud, deep snow,
and while climbing or descending
steep hills. If the vehicle has StabiliTrak
®,
shifting into Four-Wheel Drive Low
will turn Traction Control and
StabiliTrak off. See StabiliTrak
®
System on page 9‑53.
{WARNING
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
before placing the transfer case in
N (Neutral). SeeParking Brake on
page 9‑51.
N (Neutral): Shift the vehicle's
transfer case to N (Neutral) only
when towing the vehicle. See
Recreational Vehicle Towing on
page 10‑87 orTowing the Vehicle
on page 10‑87 for more information.

Black plate (53,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-53
Ride Control Systems
StabiliTrak®System
The vehicle has a vehicle stability
enhancement system called
StabiliTrak. It is an advanced
computer-controlled system that
assists the driver with directional
control of the vehicle in difficult
driving conditions.
StabiliTrak activates when the
computer senses a discrepancy
between the intended path and the
direction the vehicle is actually
traveling. StabiliTrak selectively
applies braking pressure at any one
of the vehicle's brakes to assist the
driver with keeping the vehicle on
the intended path.
StabiliTrak is on automatically
whenever the vehicle is started. To
assist with directional control of the
vehicle, the system should always
be left on. Trailer Sway Control
(TSC) is also on automatically when
the vehicle is started. SeeTrailer
Sway Control (TSC) on page 9‑100. When the vehicle is started and
begins to move, the system
performs several diagnostic checks
to insure there are no problems.
The system may be heard or felt
while it is working. This is normal
and does not mean there is a
problem with the vehicle.
If cruise control is being used when
StabiliTrak activates, the cruise
control automatically disengages.
The cruise control can be
re-engaged when road conditions
allow. See
Cruise Control on
page 9‑56.
If the system fails to turn on or
activate, the StabiliTrak light along
with a message will be displayed on
the Driver Information Center (DIC).
If a DIC message appears, make
sure the StabiliTrak system has not
been turned off using the Traction
Control System (TCS)/StabiliTrak
button. Then turn the vehicle off,
wait 15 seconds, and then turn it
back on again to reset the system.
If any of the messages still appear
on the DIC, the vehicle should be taken in for service. For more
information on the DIC messages,
see
Ride Control System Messages
on page 5‑42.
The StabiliTrak light will flash on the
instrument panel cluster when the
system or the TSC feature is both
on and activated.
The system may be heard or felt
while it is working; this is normal.
The TCS/StabiliTrak button is
located on the instrument panel.

Black plate (54,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-54 Driving and Operating
The traction control part of
StabiliTrak can be turned off by
pressing and releasing the TCS/
StabiliTrak button if both systems
(traction control and StabiliTrak)
were previously on.
To disable both TCS and
StabiliTrak, press and hold the TCS/
StabiliTrak button until the
StabiliTrak OFF light illuminates and
the appropriate DIC message
displays. This will also disable the
TSC feature.
Traction control and StabiliTrak can
be turned on by pressing and
releasing the TCS/StabiliTrak button
if they are not automatically shut off
for any other reason. This will also
enable the TSC feature.When the TCS or StabiliTrak system
is turned off, the StabiliTrak light
and the appropriate message will be
displayed on the DIC to warn the
driver. The vehicle will still have
brake-traction control when traction
control is off, but will not be able to
use the engine speed management
system. See
“Traction Control
Operation” next for more
information.
When the TCS has been turned off,
system noises may still be heard as
a result of the brake-traction control
coming on.
It is recommended to leave the
system on for normal driving
conditions, but it may be necessary
to turn the system off if the vehicle
is stuck in sand, mud, ice or snow,
and you want to “rock”the vehicle to
attempt to free it. It may also be
necessary to turn off the system
when driving in extreme off-road
conditions where high wheel spin is
required. See If the Vehicle Is Stuck
on page 9‑14. When the transfer case is in 4LO,
the stability system is automatically
disabled, the StabiliTrak light comes
on, and the appropriate message
will appear on the DIC. Both traction
control and StabiliTrak are
automatically disabled in this
condition.
Traction Control Operation
The TCS is part of the StabiliTrak
system. Traction control limits wheel
spin by reducing engine power to
the wheels (engine speed
management) and by applying
brakes to each individual wheel
(brake-traction control) as
necessary.
The TCS is enabled automatically
when the vehicle is started. It will
activate and the StabiliTrak light will
flash if it senses that any of the
wheels are spinning or beginning to
lose traction while driving. If traction
control is turned off, only the
brake-traction control portion of
traction control will work. The
engine speed management will be