2009 HUMMER H2 torque

Automatic Transmission Operation
The vehicle has a Hydra-Matic®6L80 automatic
transmission, and has 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.
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 may notice an increase in the effort
to shift out of P (Park). See Torque Lock (Automatic
Transmission) underShifting Into Park on page 2-43
for more information.{CAUTION:
It is dangerous to get out of the vehicle if the shift
lever is not fully in P (Park) with the parking brake
rmly 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). SeeShifting Into
Park on page 2-43. If you are pulling a trailer, see
Towing a Trailer on page 4-55.
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.
2-32

Tow/Haul Mode
The vehicle has 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 while towing or
hauling heavy loads.
Press the button located on the instrument panel to the
right of the steering wheel to turn tow/haul on or off. While
tow/haul is on, a light on the instrument panel cluster
comes on.
SeeTow/Haul Mode Light on page 3-44for more
information.
Also see “Tow Haul Mode” underTowing a Trailer on
page 4-55for more information.
Grade Braking
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 2-32for 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 4-55for more
information.
2-36

Transfer Case Dial
The transfer case dial is
located to the right of the
instrument panel cluster.
Use this switch to shift into
and out of the different
Full-Time Four-Wheel
Drive modes.
The transfer case is a part of the Full-Time Four-Wheel
Drive system and allows the following four different
modes of operation:
4
m(Full-Time Four-Wheel Drive):This setting is
used for driving in most street and highway situations.
It can be used for light or variable off-road conditions.
4
mQ(Four-Wheel-High Lock):Use this mode
when you need extra traction in most off-road situations
such as sand, mud, snow, or level, rocky trails.4
nQ(Four-Wheel-Low Lock):This mode delivers
extra torque to all four wheels and is used for extreme
off-road conditions. Choose Four-Wheel-Low Lock
while driving off-road in deep sand, mud, or snow and
climbing or descending steep hills.
When in this mode you can also choose to lock the rear
axle for additional traction in extreme off-road situations.
SeeLocking Rear Axle on page 4-10.
Notice:Operating the vehicle in
Four-Wheel-Low Lock above 50 mph (80 km/h)
for any extended period of time could cause damage
to the transfer case. Do not operate the vehicle in
Four-Wheel-Low Lock above 50 mph (80 km/h) for
extended periods.
{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 2-42.
2-38

Torque Lock
If you are parking on a hill and you do not shift the
transmission into P (Park) properly, the weight of the
vehicle may put too much force on the parking pawl in
the transmission. You may nd it difficult to pull the
shift lever out of P (Park). This is called “torque lock.”
To prevent torque lock, set the parking brake and
then shift into P (Park) properly before you leave the
driver seat. To nd out how, seeShifting Into Park
on page 2-43.
When you are ready to drive, move the shift lever out of
P (Park) before you release the parking brake.
If torque lock does occur, you may need to have another
vehicle push yours a little uphill to take some of the
pressure from the parking pawl in the transmission,
so you can pull the shift lever out of P (Park).
Shifting Out of Park
The 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, and
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.
SeeJump Starting on page 5-42for more information.
To shift out of P (Park):
1. Apply the brake pedal.
2. Press the shift lever button.
3. Move the shift lever to the desired position.
If you still are unable to shift out of P (Park):
1. Fully release the shift lever button.
2. While holding down the brake pedal, press the shift
lever button again.
3. Move the shift lever to the desired position.
If you still cannot move the shift lever from P (Park),
see your dealer/retailer.
2-44

Brake and Accelerator Operation
Techniques for Off-Road Driving
For logs, walls, rocks, severe ditches,
hills, sand, etc.
1. Bring the vehicle to a complete stop. Do not rev the
engine.
2. Select the proper transmission and transfer case
gear range; usually 1 (First) gear, 4LO LOCK for
such obstacles.
3. If wheel spin is experienced, maintain steady throttle,
with your foot off the brake pedal, to allow the
Traction Control System (TCS) to control the wheel
spin. TCS might not operate if the brakes are
applied.
4. If wheel spin cannot be controlled by the TCS, fully
press the brake pedal with your left foot so all
wheel spin is stopped.
5. Back away from the obstacle so that a new
approach can be tried.
6. As the rst wheel crosses the obstacle, be prepared
to alternate the brake and accelerator pedal to
maintain control and avoid tire drop-off from
obstacles. Repeat this process for the other wheels.
For mounds, washouts, loose up-hill
slopes, ditches, etc.
When wheel spin occurs as the vehicle is moving, the
driver may notice a slight shaking or shuddering of
the vehicle. This should be stopped as soon as possible
to prevent damage to vehicle components. This is the
indication that a loss of traction is occurring on this
terrain. The operator should:
1. Reduce speed and apply the brakes.
2. Assess the terrain properly and adjust vehicle
speed and gear ranges accordingly: 4HI position
for higher speeds and 4LO LOCK for more torque
and lower speeds. Transmission 1 (First) gear
is generally recommended.
3. Apply slight pressure to the brake when the shaking
or shuddering sensation is felt, keeping the vehicle
moving in a controlled manner.
4. Be prepared to alternate between braking and
accelerating through the adverse terrain.
4-21

Brake Wear
This vehicle has disc brakes. Disc brake pads have
built-in wear indicators that make a high-pitched warning
sound when the brake pads are worn and new pads
are needed. The sound can come and go or be heard all
the time the vehicle is moving, except when applying
the brake pedal rmly.
{CAUTION:
The brake wear warning sound means that soon
the brakes will not work well. That could lead to an
accident. When the brake wear warning sound is
heard, have the vehicle serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can cause a brake
squeal when the brakes are rst applied or lightly applied.
This does not mean something is wrong with the brakes.Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to torque specications in
Capacities and Specifications on page 5-117.
Brake linings should always be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer/retailer if the brake pedal does not
return to normal height, or if there is a rapid increase in
pedal travel. This could be a sign that brake service
might be required.
Brake Adjustment
Every brake stop, the disc brakes adjust for wear.
5-40

Reset the Tire Pressure Monitor System. SeeTire
Pressure Monitor Operation on page 5-66.
Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and Specifications on page 5-117.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the
vehicle. In an emergency, you can use a
cloth or a paper towel to do this; but be sure
to use a scraper or wire brush later, if
needed, to get all the rust or dirt off. See
Changing a Flat Tire on page 5-80.
Make sure the spare tire is stored securely. Push,
pull, and then try to rotate or turn the tire. See
Storing a Flat or Spare Tire and Tools (SUT) on
page 5-95orStoring a Flat or Spare Tire and
Tools (SUV) on page 5-98.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
inuence when you need new tires.
One way to tell when it is
time for new tires is to
check the treadwear
indicators, which appear
when your tires have
only 1/16 inch (1.6 mm) or
less of tread remaining.
Some commercial
truck tires may not have
treadwear indicators.
5-71

13. Tighten each wheel nut by hand. Then use the
wheel wrench to tighten the nuts by turning it
clockwise until the wheel is held against the hub.
You will not be tightening the nuts fully yet.
14. Lower the vehicle by turning the wheel wrench
counterclockwise. Then lower the jack completely.
{CAUTION:
Incorrect or improperly tightened wheel nuts can
cause the wheel to come loose and even come
off. This could lead to a crash. If you have to
replace them, be sure to get new original
equipment wheel nuts. Stop somewhere as soon
as you can and have the nuts tightened with a
torque wrench to the proper torque specication.
SeeCapacities and Specifications on page 5-117
for wheel nut torque specication.
Notice:Improperly tightened wheel nuts can lead
to brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specication. SeeCapacities and
Specifications on page 5-117for the wheel nut
torque specication.
5-94