2011 GMC SIERRA Owner's Manual

Black plate (43,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-43
Shifting Out of Park
This vehicle is equipped with
an electronic shift lock release
system. The shift lock release is
designed to:
.Prevent ignition key removal
unless the shift lever is in
P (Park) with the shift lever
button fully released.
.Prevent movement of the shift
lever out of P (Park), unless
the ignition is in ON/RUN or
ACC/ACCESSORY and the
regular brake pedal is applied.
The shift lock release is always
functional except in the case of an
uncharged or low voltage (less than
9 volt) battery.
If the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. See Jump Starting on
page 10‑98 for more information. To shift out of P (Park) use the
following:
1. Apply the brake pedal.
2. Move the shift lever to the
desired position.
If you still are unable to shift out of
P (Park):
1. Ease the pressure on the shift lever.
2. While holding down the brake pedal, press the shift lever all
the way into P (Park).
3. Move the shift lever to the desired position.
If you are still having a problem
shifting, then have the vehicle
serviced soon.
Parking Over Things
That Burn
{WARNING
Things that can burn could touch
hot exhaust parts under the
vehicle and ignite. Do not park
over papers, leaves, dry grass,
or other things that can burn.

Black plate (44,1)GMC Sierra Owner Manual - 2011
9-44 Driving and Operating
Active Fuel Management®
Vehicles with V8 engines may
have Active Fuel Management™.
This system allows the engine to
operate on either all or half of its
cylinders, depending on the driving
conditions.
When less power is required, such
as cruising at a constant vehicle
speed, the system will operate in
the half cylinder mode, allowing
the vehicle to achieve better fuel
economy. When greater power
demands are required, such as
accelerating from a stop, passing,
or merging onto a freeway, the
system will maintain full-cylinder
operation.
If the vehicle has an Active
Fuel Management™indicator, see
Driver Information Center (DIC) on
page 5‑33 for more information on
using this display.
Engine Exhaust
{WARNING
Engine exhaust contains Carbon
Monoxide (CO) which cannot be
seen or smelled. Exposure to CO
can cause unconsciousness and
even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas
with poor ventilation (parking
garages, tunnels, deep snow
that may block underbody
airflow or tail pipes).
.The exhaust smells or
sounds strange or different.
.The exhaust system leaks
due to corrosion or damage.
.The vehicle exhaust system
has been modified, damaged
or improperly repaired.
(Continued)
WARNING (Continued)
.There are holes or openings
in the vehicle body from
damage or after-market
modifications that are not
completely sealed.
If unusual fumes are detected or
if it is suspected that exhaust is
coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired
immediately.
Never park the vehicle with the
engine running in an enclosed
area such as a garage or a
building that has no fresh air
ventilation.

Black plate (45,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-45
Running the Vehicle
While Parked
It is better not to park with the
engine running. But if you ever have
to, here are some things to know.
{WARNING
Idling a vehicle in an enclosed
area with poor ventilation is
dangerous. Engine exhaust may
enter the vehicle. Engine exhaust
contains Carbon Monoxide (CO)
which cannot be seen or smelled.
It can cause unconsciousness
and even death. Never run the
engine in an enclosed area
that has no fresh air ventilation.
For more information, seeEngine
Exhaust on page 9‑44.
{WARNING
It can be dangerous to get out
of the vehicle if the automatic
transmission shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when
the engine is running unless
you have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
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).
{WARNING
Four-wheel drive vehicles with the
transfer case in N (Neutral) will
allow the vehicle to roll, even if
the automatic transmission shift
lever is in P (Park). So, be sure
the transfer case is in a drive
gear —not in N (Neutral). Always
set the parking brake.
Follow the proper steps to be
sure the vehicle will not move.
See Shifting Into Park on
page 9‑41.
If pulling a trailer, see Driving
Characteristics and Towing Tips on
page 9‑91.

Black plate (46,1)GMC Sierra Owner Manual - 2011
9-46 Driving and Operating
Automatic
Transmission
If the vehicle is a hybrid, see
the hybrid supplement for more
information.
Vehicles with an automatic
transmission have an electronic
shift position indicator within
the instrument panel cluster.
This display comes on when
the ignition key is turned to
the ON/RUN position.There are several different positions
for the shift lever.
Hydra-Matic®4-Speed Automatic
Transmission
Heavy Duty 6-Speed
Automatic Transmission Shown (Light Duty 6‐Speed Similar)
See “Range Selection Mode” under
Manual Mode on page 9‑50. P (Park):
This position locks the
rear wheels. It is the best position
to use when starting the engine
because the vehicle cannot move
easily. When parked on a hill,
especially when the vehicle has a
heavy load, you might notice an
increase in the effort to shift out of
P (Park). See “Torque Lock” under
Shifting Into Park on page 9‑41 for
more information.
{WARNING
It is dangerous to get out of the
vehicle if the shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when
the engine is running unless
you have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
(Continued)

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.