GMC SIERRA 2011 Owner's Manual

Black plate (47,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-47
WARNING (Continued)
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
SeeShifting Into Park on
page 9‑41. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑91.
{WARNING
If you have Four-Wheel Drive, the
vehicle will be free to roll —even
if the shift lever is in P (Park) —if
the transfer case is in Neutral.
So, be sure the transfer case is
in a drive gear, Two-Wheel Drive
High or Four-Wheel Drive High or
Four-Wheel Drive Low —not in
Neutral. See Shifting Into Park
on page 9‑41. R (Reverse):
Use this gear to
back up.
Notice: 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 on page 9‑23.
N (Neutral): In this position, the
engine does not connect with the
wheels. To restart when you are
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.
Notice: 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.

Black plate (48,1)GMC Sierra Owner Manual - 2011
9-48 Driving and Operating
D (Drive):This position is for
normal driving. It provides the best
fuel economy. If you need more
power for passing, and you are:
.Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
.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.
D (Drive) can be used when towing
a trailer, carrying a heavy load,
driving on steep hills, or for off-road
driving. You might want to shift
the transmission to a lower gear
selection if the transmission shifts
too often. Downshifting the transmission in
slippery road conditions could result
in skidding. See
“Skidding”under
Loss of Control on page 9‑6.
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. The transmission uses
adaptive shift controls.
Adaptive shift controls continually
compares key shift parameters to
pre-programmed ideal shifts stored
in the transmissions 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 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 Allison Transmission and
Hydra-Matic 6-Speed transmission's
gear shifting could be delayed
providing more stable shifts until
the engine warms up. Shifts could
be more noticeable with a cold
transmission. This difference in
shifting is normal.

Black plate (49,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-49
M (Manual Mode):This position
is available on vehicles with the
Allison Transmission or Hydra-Matic
6-Speed transmission. It lets
drivers select the range of gears
appropriate for current driving
conditions. If the vehicle has this
feature, see “Range Selection
Mode” underManual Mode on
page 9‑50.
3 (Third): This position is also used
for normal driving. It reduces vehicle
speed more than D (Drive) without
using the brakes. You might choose
3 (Third) instead of D (Drive) when
driving on hilly, winding roads, when
towing a trailer, so there is less
shifting between gears and when
going down a steep hill.
2 (Second): This position reduces
vehicle speed even more than
3 (Third) without using the brakes.
You can use 2 (Second) on hills. It can help control vehicle speed as
you go down steep mountain roads,
but then you would also want to use
the brakes off and on.
If you manually select 2 (Second)
in an automatic transmission, the
transmission will start in second
gear. You can use this feature for
reducing the speed of the rear
wheels when you are trying to
start the vehicle from a stop on
slippery road surfaces.
1 (First):
For the Hydra-Matic
4-Speed transmission this position
reduces vehicle speed even more
than 2 (Second) without using the
brakes. You can use it on very steep
hills, or in deep snow or mud. If the
shift lever is put in 1 (First) while
the vehicle is moving forward, the
transmission does not shift into first
gear until the vehicle is going slowly
enough. For an Allison Transmission or
Hydra-Matic 6-Speed transmission,
this position reduces vehicle speed
without using the brakes. You can
use it for major/severe downgrades
and off-road driving where the
vehicle would otherwise accelerate
due to steepness of grade. When
you shift to 1 (First) it provides the
lowest gear appropriate to current
road speed and continues to
downshift as the vehicle slows,
eventually downshifting to
1 (First) gear.
Notice:
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 you are stuck, do not
spin the tires. When stopping on
a hill, use the brakes to hold the
vehicle in place.

Black plate (50,1)GMC Sierra Owner Manual - 2011
9-50 Driving and Operating
Manual Mode
Range Selection Mode
(Allison®Transmission or
Hydra-Matic®6-Speed
Transmission)
The vehicle may have a Range
Selection Mode. The Range
Selection Mode helps control
the vehicle's transmission and
vehicle speed while driving down
hill or towing a trailer by letting you
select a desired range of gears. To use this feature, do the following:
1. Move the shift lever to
M (Manual Mode).
2. Press the plus/minus buttons, located on the steering column
shift lever, to select the desired
range of gears for current driving
conditions.
When M (Manual Mode) is selected
a number displays next to the M,
indicating the current gear.
This number is the highest gear
that can be used. However, the
vehicle can automatically shift to
lower gears as it adjusts to driving
conditions. This means that all
gears below that number are
available. When 5 (Fifth) is selected,
1 (First) through 5 (Fifth) gears are
automatically shifted by the vehicle,
but 6 (Sixth) cannot be used until
the plus/minus button located on
the steering column lever is used
to change to the gear. Grade Braking is not available when
Range Selection Mode is active.
See
Tow/Haul Mode on page 9‑51.
While using Range Selection Mode,
Cruise Control and the Tow/Haul
Mode can be used.
If the vehicle has an exhaust
brake, it can also be used, but will
not automatically downshift the
transmission. See Exhaust Brake in
the Duramax Diesel supplement.
Notice: 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 you are stuck, do not
spin the tires. When stopping on
a hill, use the brakes to hold the
vehicle in place.

Black plate (51,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-51
Low Traction Mode
If your vehicle has the Allison
Transmission, or the Hydra-Matic
6-Speed Automatic Transmission,
it has a Low Traction Mode that
can assist 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 after it detects
wheel slip, preventing the tires from
spinning.
Tow/Haul Mode
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 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 is on, a light on the
instrument panel cluster will
come on.
See
Tow/Haul Mode Light on
page 5‑29 for more information.
Also see “Tow/Haul Mode” under
Towing Equipment on page 9‑112
for more information.

Black plate (52,1)GMC Sierra Owner Manual - 2011
9-52 Driving and Operating
Tow/Haul Mode
(Allison Transmission
or Hydra-Matic 6-Speed
Automatic Transmission)
Vehicles with an Allison
Transmission or Hydra-Matic
6-Speed 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 towing or hauling
heavy loads.Turn the Tow/Haul Mode on and
off by pressing the button, located
on the end of the shift lever. When
the tow/haul is on, a light on the
instrument panel cluster will
come on.
See
Tow/Haul Mode Light on
page 5‑29 for more information.
Also see “Tow/Haul Mode” under
Towing Equipment on page 9‑112
for more information.
Grade Braking
(Allison Transmission
or Hydra-Matic 6-Speed
Automatic Transmission)
The Grade Braking shift modes
can be activated by pressing the
button on the end of the shift control
lever. While in Range Selection
Mode, Grade Braking is deactivated
allowing the driver to select a
desired range of gears.
Grade Braking is only active while
the Tow/Haul Mode is selected and
you are not in the Range Selection
Mode. See “Tow/Haul Mode” listed
previously and Manual Mode on
page 9‑50 for more information
on the Range Selection Mode.

Black plate (53,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-53
Grade Braking assists in
maintaining desired vehicle
speeds when driving on
downhill grades by automatically
implementing a shift schedule that
utilizes the engine and transmission
to slow the vehicle. This reduces
wear on the braking system and
increases control of the vehicle.
Grade Braking monitors vehicle
speed, acceleration, engine torque
and brake pedal usage. Using this
information, it detects when the
truck is on a downhill grade and
the driver desires to slow the
vehicle by pressing the brake.
This feature is active when
the exhaust brake is enabled
(if equipped).
Also seeTowing Equipment on
page 9‑112 for more information.Cruise Grade Braking
(Allison Transmission
or Hydra-Matic 6-Speed
Automatic Transmission)
Cruise Grade Braking assists
when driving on a downhill grade.
It maintains vehicle speed by
automatically implementing a shift
schedule that uses the engine
and the transmission to slow the
vehicle. Cruise Grade Braking
operates while Cruise Control is
engaged in Tow/Haul Mode to assist
in maintaining vehicle speed under
loaded vehicle conditions. It utilizes
vehicle acceleration and deviation
from desired speed to determine the correct gear for the operating
condition. If vehicle speed is above
the desired speed the transmission
will downshift to slow the vehicle.
If vehicle speed is near or below
desired speed the trans will upshift,
allowing vehicle speed to increase.
While in the Range Selection Mode,
Cruise Grade Braking is not
available.
This feature is active when
the exhaust brake is enabled
(if equipped).
See
“Range Selection Mode” under
Manual Mode on page 9‑50.

Black plate (54,1)GMC Sierra Owner Manual - 2011
9-54 Driving and Operating
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 9‑70.
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
The transfer case shift lever is on
the floor to the right of the driver.
Use this lever to shift into and out
of Four-Wheel Drive.

Black plate (55,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-55
A Four-Wheel Drive indicator light
comes on when you shift into
four-wheel drive and the front axle
engages. SeeFour-Wheel-Drive
Light on page 5‑29.
Some delay between shifting and
when the indicator light comes on is
normal.
Recommended Transfer Case Settings
Driving Conditions Transfer Case Settings
2m 4m4n N
Normal YES Severe YES
Extreme YES
Vehicle in Tow* YES
*See Recreational Vehicle Towing on page 10‑103 orTowing the Vehicle
on page 10‑103.
Notice: Driving on clean, dry
pavement in four-wheel drive for
an extended period of time can
cause premature wear on the
vehicle's powertrain. Do not
drive on clean, dry pavement in
Four-Wheel Drive for extended
periods of time. 4
n(Four-Wheel Drive Low):
This
setting also engages the front axle
and delivers extra torque. You may
never need Four-Wheel Drive Low.
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.

Black plate (56,1)GMC Sierra Owner Manual - 2011
9-56 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 9‑70.
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
before placing the transfer case
in N (Neutral). SeeParking Brake
on page 9‑69.
N (Neutral): Shift to this setting
only when the vehicle needs to be
towed. See Recreational Vehicle
Towing on page 10‑103 orTowing
the Vehicle on page 10‑103. 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.