2009 GMC SIERRA automatic transmission

Tow/Haul Mode (Allison Transmission®
or Hydra-Matic®6-Speed Automatic
Transmission)
Vehicles with an Allison 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.
SeeTow/Haul Mode Light on page 3-51for more
information.
Also see “Tow Haul Mode” underTowing a Trailer on
page 4-51for more information.
2-35

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 andAutomatic
Transmission Operation on page 2-28for more
information on the Range Selection Mode. 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.
Also seeTowing a Trailer on page 4-51for 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 Select Mode (RSM) mode, cruise
grade braking is not available.
SeeAutomatic Transmission Operation on page 2-28.
2-36

If the vehicle has StabiliTrak®, shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. SeeStabiliTrak®System on page 4-6.
{CAUTION:
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 2-50.
N (Neutral):Shift the vehicle’s transfer case
to N (Neutral) only when towing the vehicle. See
Recreational Vehicle Towing on page 4-45orTowing
Your Vehicle on page 4-45for more information.If the SERVICE 4-Wheel Drive message stays on,
you should take the vehicle to your dealer/retailer
for service. See “Service 4-Wheel Drive message”
underDIC Warnings and Messages on page 3-66.
Shifting Into Four-Wheel-Drive High
or AUTO (Automatic Four-Wheel Drive)
Turn the knob to the Four-Wheel-Drive High or AUTO
position. This can be done at any speed, except when
shifting from Four-Wheel-Drive Low. The indicator light
will ash while shifting. It will remain on when the shift is
completed.
Shifting Into Two-Wheel-Drive High
Turn the knob to the Two-Wheel-Drive High position.
This can be done at any speed, except when shifting
from Four-Wheel-Drive Low. The indicator light will
ash while shifting. It will remain on when the shift
is completed.
2-47

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.
{CAUTION:
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 2-55.
{CAUTION:
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 rmly set.
CAUTION: (Continued)
CAUTION: (Continued)
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).
{CAUTION:
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. SeeShifting Into Park on page 2-52.
If pulling a trailer, seeTowing a Trailer on page 4-51.
2-56

The main components of the instrument panel are the following:
A.Outlet Adjustment on page 3-33.
B.Turn Signal/Multifunction Lever on page 3-9.
C.Driver Information Center (DIC) on page 3-53.
D.Hazard Warning Flashers on page 3-8.
E.Instrument Panel Cluster on page 3-34.
F. Shift Lever. SeeAutomatic Transmission
Operation on page 2-28. Tow/Haul Selector Button
(If Equipped). SeeTow/Haul Mode on page 2-34.
Range Selection Mode (Allison Transmission
and Hydra-Matic
®6-Speed Button (If Equipped).
SeeAutomatic Transmission Operation on
page 2-28.
G.Audio System(s) on page 3-85.
H.Instrument Panel Storage on page 2-81.
I. Integrated Trailer Brake Controller (If Equipped).
SeeTowing a Trailer on page 4-51.
J.Exterior Lamps on page 3-16.
K.Hood Release on page 5-13.
L.Parking Brake on page 2-50.
M.Dome Lamp Override on page 3-20.Dome Lamps
on page 3-20.Fog Lamps on page 3-19
(If Equipped).
N.Cruise Control on page 3-13.
O.Tilt Wheel on page 3-8.P.Horn on page 3-8.
Q.Audio Steering Wheel Controls on page 3-141
(If Equipped).
R. Automatic Transfer Case Control (If Equipped).
SeeFour-Wheel Drive on page 2-37.
S. Ashtray (If Equipped). SeeAshtray(s) and Cigarette
Lighter on page 3-23.
T.StabiliTrak
®System on page 4-6(If Equipped).
Ultrasonic Rear Parking Assist (URPA) on page 2-62
(If Equipped). Pedal Adjust Button (If Equipped).
SeeAdjustable Throttle and Brake Pedal on
page 2-26. Heated Windshield Washer Fluid Button
(If Equipped).Windshield Washer on page 3-12.
U.Accessory Power Outlet(s) on page 3-22.
V.Climate Control System (With Heater Only) on
page 3-24orClimate Control System (With Air
Conditioning) on page 3-25andDual Automatic
Climate Control System on page 3-27.
W. Power Take Off (PTO) Control (If Equipped).
See Power Take Off (PTO) in the Duramax Diesel
Supplement Index.
X. Passenger Airbag Off Control (If Equipped).
SeeAirbag Off Switch on page 1-81.
Y.Glove Box on page 2-81.
3-5

The main components of the instrument panel are the following:
A.Outlet Adjustment on page 3-33.
B.Turn Signal/Multifunction Lever on page 3-9.
C.Instrument Panel Cluster on page 3-34.
D.Hazard Warning Flashers on page 3-8.
E. Shift Lever. SeeAutomatic Transmission Operation
on page 2-28.
F.Tow/Haul Mode on page 2-34(If Equipped).
G.Driver Information Center (DIC) on page 3-53.
H.Audio System(s) on page 3-85.
I.Exterior Lamps on page 3-16.
J. Integrated Trailer Brake Controller (If Equipped).
SeeTowing a Trailer on page 4-51.
K.Dome Lamp Override on page 3-20.Dome Lamps
on page 3-20.
L. Automatic Transfer Case Control. (If Equipped).
SeeFour-Wheel Drive on page 2-37.
M.Hood Release on page 5-13.
N.Parking Brake on page 2-50.
O.Cruise Control on page 3-13.P.Tilt Wheel on page 3-8.
Q.Horn on page 3-8.
R.Audio Steering Wheel Controls on page 3-141.
S.Climate Control System (With Heater Only)
on page 3-24orClimate Control System (With Air
Conditioning) on page 3-25orDual Automatic
Climate Control System on page 3-27(If Equipped).
T.Accessory Power Outlet(s) on page 3-22.
Cigarette Lighter (If Equipped). SeeAshtray(s)
and Cigarette Lighter on page 3-23.
U.StabiliTrak
®System on page 4-6(If Equipped).
Pedal Adjust Button (If Equipped). SeeAdjustable
Throttle and Brake Pedal on page 2-26.Ultrasonic
Rear Parking Assist (URPA) on page 2-62
(If Equipped). Heated Windshield Washer Fluid
Button (If Equipped). SeeWindshield Washer
on page 3-12.
V. Passenger Airbag Off Control (If Equipped).
SeeAirbag Off Switch on page 1-81.
W.Glove Box on page 2-81.
3-7

Cruise Control
{CAUTION:
Cruise control can be dangerous where you cannot
drive safely at a steady speed. So, do not use the
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 excessive wheel slip, and you could lose
control. Do not use cruise control on slippery roads.
With cruise control, a speed of about 25 mph (40 km/h)
or more can be maintained without keeping your foot
on the accelerator. This can really help on long
trips. Cruise control does not work at speeds below
about 25 mph (40 km/h).When the brakes are applied, cruise control is turned off.
For vehicles with an Allison
®or Hydra-Matic 6-speed
automatic transmission, see “Grade Braking and Cruise
Grade Braking (Allison Transmission) underTow/Haul
Mode on page 2-34for an explanation of how cruise
control interacts with the Range Selection Mode,
tow/haul and grade braking systems.
For vehicles with the StabiliTrak
®system that begins
to limit wheel spin while you are using cruise control,
the cruise control will automatically disengage.
SeeStabiliTrak
®System on page 4-6. When road
conditions allow the cruise control to be safely used
again, it can be turned back on.
3-13

2(Headlamps):Turns on the headlamps together
with the following:
Parking Lamps
Instrument Panel Lights
Taillamps
License Plate Lamps
When the headlamps are turned on while the vehicle is
on, the headlamps turn off automatically 10 minutes
after the ignition is turned off. When the headlamps are
turned on while the vehicle is off, the headlamps will
stay on for 10 minutes before automatically turning off
to prevent the battery from being drained. Turn the
headlamp control to off and then back to the headlamp
on position to make the headlamps stay on for an
additional 10 minutes.
Push the turn signal/multifunction lever toward the
instrument panel to change the headlamps from low
beam to high beam.
Headlamps on Reminder
A reminder chime will sound when the headlamps or
parking lamps are manually turned on and the ignition is
off and a door is open. To disable the chime, turn the
light off.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier
for others to see the front of your vehicle during the day.
Fully functional daytime running lamps are required
on all vehicles rst sold in Canada.
The DRL system will come on when the following
conditions are met:
The ignition is on.
The exterior lamps control is in AUTO.
The transmission is not in P (Park).
The light sensor determines it is daytime.
When the DRL are on, only the DRL lamps will be on.
The taillamps, sidemarker, instrument panel lights,
and other lamps will not be on.
When it begins to get dark, the automatic headlamp
system will switch from DRL to the headlamps.
To turn off the DRL lamps, turn the exterior lamps
control to the OFF position and then release.
For vehicles rst sold in Canada, the transmission
must be in the P (Park) position, before the DRL lamps
can be turned off.
3-17