transmission HUMMER H2 2009 Owner's Guide

Things not to do if the vehicle stalls, or is about to stall,
when going up a hill:
Never attempt to prevent a stall by shifting into
N (Neutral) to rev-up the engine and regain forward
momentum. This will not work. The vehicle can
roll backward very quickly and could go out
of control.
Never try to turn around if about to stall when going
up a hill. If the hill is steep enough to stall the vehicle,
it is steep enough to cause it to roll over. If you
cannot make it up the hill, back straight down the hill.
If, after stalling, you try to back down the hill and decide
you just cannot do it, set the parking brake, shift to
P (Park), and turn off the engine. Leave the vehicle and
go get some help. Exit on the uphill side and stay clear of
the path the vehicle would take if it rolled downhill. Do not
shift the transfer case to Neutral when you leave the
vehicle. Leave it in some gear.
{CAUTION:
Shifting the transfer case to Neutral can cause
your vehicle to roll even if the transmission is in
P (Park). This is because the Neutral position on
the transfer case overrides the transmission. You
or someone else could be injured. If you are going
to leave your vehicle, set the parking brake and
shift the transmission to P (Park). But do not shift
the transfer case to Neutral. Leave the transfer
case in the 4 HI, 4 HI Lock, or 4 LO Lock position.
4-28

Driving Downhill
When off-roading takes you downhill, consider:
How steep is the downhill? Will I be able to maintain
vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts? Logs?
Boulders?
What is at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, try to keep
the vehicle headed straight down. Use a low gear
so engine drag can help the brakes so they do not have
to do all the work. Descend slowly, keeping the
vehicle under control at all times.
{CAUTION:
Heavy braking when going down a hill can cause
your brakes to overheat and fade. This could cause
loss of control and a serious accident. Apply the
brakes lightly when descending a hill and use a low
gear to keep vehicle speed under control.Things not to do when driving down a hill:
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that is not too
steep to drive down might be too steep to drive
across. The vehicle could roll over.
Never go downhill with the transmission in
N (Neutral), called free-wheeling. The brakes will
have to do all the work and could overheat
and fade.
Vehicles are much more likely to stall when going uphill,
but if it happens when going downhill:
1. Stop the vehicle by applying the regular brakes and
apply the parking brake.
2. Shift to P (Park). While still braking, restart the
engine.
3. Shift back to a low gear, release the parking brake,
and drive straight down.
4. If the engine will not start, get out and get help.
4-29

Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep the vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a
lower gear.
{CAUTION:
If you do not shift down, the brakes could get so
hot that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let the engine
assist the brakes on a steep downhill slope.
{CAUTION:
Coasting downhill in N (Neutral) or with the ignition
off is dangerous. The brakes will have to do all the
work of slowing down and they could get so hot
that they would not work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have the engine running
and the vehicle in gear when going downhill.
Stay in your own lane. Do not swing wide or cut
across the center of the road. Drive at speeds
that let you stay in your own lane.
Top of hills: Be alert — something could be in your
lane (stalled car, accident).
Pay attention to special road signs (falling rocks
area, winding roads, long grades, passing or
no-passing zones) and take appropriate action.
SeeOff-Road Driving on page 4-15for information
about driving off-road.
4-36

Rocking Your Vehicle to Get It Out
Turn the steering wheel left and right to clear the area
around the front wheels. The traction control system
activates when the system senses that the wheels are
spinning. Shift back and forth between R (Reverse) and a
forward gear, spinning the wheels as little as possible.
To prevent transmission wear, wait until the wheels stop
spinning before shifting gears. Release the accelerator
pedal while you shift, and press lightly on the accelerator
pedal when the transmission is in gear. Slowly spinning
the wheels in the forward and reverse directions causes a
rocking motion that could free the vehicle. If that does not
get the vehicle out after a few tries, it might need to be
towed out. Or, you can use the recovery loops. If the
vehicle does need to be towed out, seeTowing Your
Vehicle on page 4-50.
Recovery Loops
{CAUTION:
These loops, when used, are under a lot of force.
Keep people away from the vicinity of the loops
and any chains or cables during use. Always pull
the vehicle straight out. Never pull on the loops at
a sideways angle. The loops could break off and
you or others could be injured from the chain or
cable snapping back.
Notice:Never use the recovery loops to tow the
vehicle. Your vehicle could be damaged and it would
not be covered by warranty.
4-40

Put your transmission in N (Neutral).
Use your regular brakes to hold your vehicle in
place and block the wheels to keep the vehicle from
moving.
Notice:Using a power winch with the transmission
in gear to pull out another vehicle may damage
the transmission. When operating a power winch,
always leave the transmission in N (Neutral).
Notice:Driving your vehicle through an automatic
car wash with the winch installed, can cause
damage to your vehicle and the car wash. Always
remove the winch from your vehicle before using an
automatic car wash. SeeWashing Your Vehicle
on page 5-105for more information.
If you are using a winch to pull out your own vehicle,
follow the winch manufacturer’s guidelines for self
recovery and observe the following to prevent damage
to your vehicle:
Do not self recover your vehicle by wrapping the
winch cable around an object (such as a pulley
block or tree) and attaching it back to your vehicle’s
recovery loops.
Always attach the winch cable directly to a solid
anchor directly in front of your vehicle to achieve
a straight line pull.
Loading the Vehicle
It is very important to know how much weight your
vehicle can carry. This weight is called the vehicle
capacity weight and includes the weight of all
occupants, cargo, and all nonfactory-installed
options. Two labels on your vehicle show how much
weight it may properly carry, the Tire and Loading
Information label and the Certication/Tire label.
{CAUTION:
Do not load the vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do, parts
on the vehicle can break, and it can change
the way your vehicle handles. These could
cause you to lose control and crash. Also,
overloading can shorten the life of the
vehicle.
4-44

Dinghy Towing
This full-time four-wheel-drive vehicle can be dinghy
towed from the front. These vehicles can also be towed
by placing them on a platform trailer with all four wheels
off the ground. These vehicles cannot be towed using
a dolly.
Use the following procedure to tow the vehicle:
1. Shift the transmission to P (Park).
2. Turn the engine off, but leave the ignition in
ACC/ACCESSORY.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the tow
vehicle.
{CAUTION:
Shifting a full-time four-wheel-drive vehicle’s
transfer case into N (Neutral) can cause the vehicle
to roll even if the transmission is in P (Park). The
driver or others could be injured. Make sure the
parking brake is rmly set before the transfer case
is shifted to N (Neutral).
5. Shift the transfer case to N (Neutral). SeeFull-Time
Four-Wheel Drive on page 2-37for the proper
procedure to select the N (Neutral) position for the
vehicle.
6. Release the parking brake only after the vehicle
being towed is rmly attached to the towing
vehicle.
7. Turn the ignition to ACC/ACCESSORY.
8. Disconnect the battery if the vehicle will be towed
for long distances or long periods of time.
When towing the vehicle for extended periods of time,
start the vehicle as often as possible to prevent
battery drain. This should only be done when the tow
vehicle is parked.
4-51

Pulling A Trailer
Here are some important points:
There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
the rig will be legal, not only where you live but
also where you will be driving. A good source for
this information can be state or provincial police.
Consider using a sway control. See “Hitches” later
in this section.
Do not tow a trailer at all during the rst 500 miles
(800 km) the new vehicle is driven. The engine,
axle or other parts could be damaged.
Then, during the rst 500 miles (800 km) that a
trailer is towed, do not drive over 50 mph (80 km/h)
and do not make starts at full throttle. This helps
the engine and other parts of the vehicle wear in at
the heavier loads.
Vehicles can tow in D (Drive). Shift the transmission
to a lower gear if the transmission shifts too often
under heavy loads and/or hilly conditions. See
“Tow/Haul Mode” following.Three important considerations have to do with weight:
The weight of the trailer
The weight of the trailer tongue
The weight on the vehicle’s tires
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how the rig is used. For example, speed,
altitude, road grades, outside temperature and how
much the vehicle is used to pull a trailer are all
important. It can depend on any special equipment on
the vehicle, and the amount of tongue weight the vehicle
can carry. See “Weight of the Trailer Tongue” later in
this section for more information.
Maximum trailer weight is calculated assuming only the
driver is in the tow vehicle and it has all the required
trailering equipment. The weight of additional optional
equipment, passengers and cargo in the tow vehicle
must be subtracted from the maximum trailer weight.
4-56

Tow/Haul Mode
Pressing this button at
the end of the shift lever
turns on and off the
tow/haul mode.
This indicator light on the
instrument panel cluster
comes on when the
tow/haul mode is on.
Tow/Haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. SeeTow/Haul Mode
on page 2-36for more information.Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75 percent
of the vehicle’s Gross Combined Weight Rating (GCWR).
See “Weight of the Trailer” later in the section. Tow/Haul
is most useful under the following driving conditions:
When pulling a heavy trailer or a large or heavy load
through rolling terrain.
When pulling a heavy trailer or a large or heavy load
in stop and go traffic.
When pulling a heavy trailer or a large or heavy load
in busy parking lots where improved low speed
control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded or
with no trailer at all will not cause damage. However,
there is no benet to the selection of Tow/Haul when the
vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission driving
characteristics and reduced fuel economy. Tow/Haul is
recommended only when pulling a heavy trailer or a large
or heavy load.
4-62

Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. The vehicle could be damaged. Avoid
making very sharp turns while trailering.
When turning with a trailer, make wider turns than
normal. Do this so the trailer will not strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
The arrows on the instrument panel ash whenever
signaling a turn or lane change. Properly hooked up, the
trailer lamps also ash, telling other drivers the vehicle
is turning, changing lanes or stopping.
When towing a trailer, the arrows on the instrument panel
ash for turns even if the bulbs on the trailer are burned
out. For this reason you may think other drivers are
seeing the signal when they are not. It is important to
check occasionally to be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might have to be used so
much that they would get hot and no longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. SeeTow/Haul Mode Light on page 3-44.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If the engine is
turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar to
engine overheating. To avoid this, let the engine run while
parked, preferably on level ground, with the automatic
transmission in P (Park) for a few minutes before turning
the engine off. If the overheat warning comes on, see
Engine Overheating on page 5-33.
4-65

Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual’s Maintenance Schedule or Index
for more information. Things that are especially important
in trailer operation are automatic transmission uid,
engine oil, axle lubricant, belts, cooling system and brake
system. It is a good idea to inspect these before and
during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Heavy-Duty Trailer Wiring Harness
Package
The vehicle is equipped with the seven-wire trailer towing
harness. This harness with a seven-pin universal trailer
connector is attached to a bracket on the hitch platform.The seven-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red/Black: Battery Feed*
Dark Blue: Trailer Brake*
*There is a location in the Underhood Fuse Block for
these circuits, but they are not connected. They should
be connected, and proper fuses installed, by your
dealer/retailer or a qualied service center.
If charging a remote (non-vehicle) battery, press the
Tow/Haul mode button located at the end of the
shift lever. This will boost the vehicle system voltage
and properly charge the battery.
4-67