2009 GMC SIERRA 1500 towing

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 on and off by pressing the
button. 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 4-53for more information.
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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 4-53for 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 and
Automatic 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 4-53for 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.
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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 3-51.
Some delay between shifting and when the indicator
light comes on is normal.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 4-47
Towing Your Vehicle on page 4-47Notice: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.
If the vehicle has StabiliTrak
®, shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. SeeStabiliTrak®System on page 4-6.
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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).
{CAUTION:
Shifting the transfer case to 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 Neutral. SeeParking Brake on
page 2-50.N (Neutral):Shift to this setting only when the vehicle
needs to be towed. SeeRecreational Vehicle Towing
on page 4-47orTowing Your Vehicle on page 4-47.
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.
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Electronic Transfer Case
The transfer case knob
is located next to the
steering column.
Use the dial to shift into and out of four-wheel drive.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeRecreational Vehicle Towing on page 4-47
Towing Your Vehicle on page 4-47You can choose among four driving settings:
Indicator lights in the dial show which setting you are in.
The indicator lights will come on briey 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/retailer for service. An indicator light ashes 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.
2-42

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 4-47orTowing
Your Vehicle on page 4-47for 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 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. See Shifting Out of
Four-Wheel-Drive Low for more information.
Shifting Into Four-Wheel Drive Low
When Four-Wheel-Drive Low is engaged, vehicle speed
should be kept below 45 mph. Extended high-speed
operation in Four-Wheel-Drive Low may damage or
shorten the life of the drivetrain.
To shift to the Four-Wheel-Drive Low position, the
ignition must be in ON/RUN and the vehicle must be
stopped or moving less than 3 mph (5 km/h) with
the transmission in N (Neutral). The preferred method
for shifting into Four-Wheel-Drive Low is to have
the vehicle moving 1 to 2 mph (1.6 to 3.2 km/h).
Turn the knob to the Four-Wheel-Drive Low position.
You must wait for the Four-Wheel-Drive Low indicator
light to stop ashing and remain on before shifting
the transmission in gear.
Notice:Shifting the transmission into gear before
the requested mode indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging the vehicle, always wait for the mode
indicator lights to stop ashing before shifting the
transmission into gear.
2-43

{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 4-47orTowing
Your Vehicle on page 4-47for 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” under
DIC 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.
Shifting Into Four-Wheel-Drive Low
When Four-Wheel-Drive Low is engaged, vehicle speed
should be kept below 45 mph. Extended high-speed
operation in Four-Wheel-Drive Low may damage
or shorten the life of the drivetrain.
To shift to the Four-Wheel-Drive Low position, the
ignition must be in ON/RUN and the vehicle must be
stopped or moving less than 3 mph (5 km/h) with
the transmission in N (Neutral). The preferred method
for shifting into Four-Wheel-Drive Low is to have
the vehicle moving 1 to 2 mph (1.6 to 3.2 km/h).
Turn the knob to the Four-Wheel-Drive Low position.
You must wait for the Four-Wheel-Drive Low indicator
light to stop ashing and remain on before shifting
the transmission into gear.
Notice:Shifting the transmission into gear before
the requested mode indicator light has stopped
ashing could damage the transfer case. To help
avoid damaging the vehicle, always wait for the mode
indicator lights to stop ashing before shifting the
transmission into gear.
2-47