transmission HUMMER H3 2006 Service Manual

When you drive over obstacles or rough terrain, keep a
rm grip on the steering wheel. Ruts, troughs, or
other surface features can jerk the wheel out of your
hands if you are not prepared.
When possible, it is a good practice to survey the
landscape ahead on foot prior to driving to observe
hidden obstacles.
When you drive over bumps, rocks, or other obstacles,
your wheels can leave the ground. If this happens,
even with one or two wheels, you cannot control the
vehicle as well or at all.
Because you will be on an unpaved surface, it is
especially important to avoid sudden acceleration,
sudden turns, or sudden braking.
In a way, off-road driving requires a different kind of
alertness from driving on paved roads and highways.
There are no road signs, posted speed limits, or signal
lights. You have to use your own good judgment
about what is safe and what is not.
Drinking and driving can be very dangerous on any
road. And this is certainly true for off-road driving. At the
very time you need special alertness and driving
skills, your reexes, perceptions, and judgment can be
affected by even a small amount of alcohol. You
could have a serious — or even fatal — accident if you
drink and drive or ride with a driver who has been
drinking. SeeDrunken Driving on page 4-3.Crossing Obstacles
Approach Angle — a Key to Mobility
If you encounter a large dip in the terrain, do not enter
straight on; enter at an angle — 15 degrees minimum
approach (A), 75 degrees maximum approach angle (B).
For very large dips, ditches, or small washes, coast
in, using the engine as a brake (transmission and
transfer case lowest gears). Then, use the low ranges in
the transmission and transfer case to power out.
4-25

Roll Your Tires Over Large Rocks
Do not straddle large
rocks; drive over them,
letting the tire envelop the
rock. The tread of the
tire is thicker and tougher
than the sidewall of the
tire and is more resilient to
impact than underbody
components.
Log Crossing
Using the proper technique, your vehicle will cross logs
up to 10 inches (25.4 cm) in diameter. Approach the
log at approximately a 15 degree angle (A) with
the transmission in FIRST (1) and the transfer case in
Four-Wheel-Low Lock and “walk” your vehicle over, one
tire at a time. As with all obstacles, face your tires
perpendicular to the object for best traction and tire life.
It may be necessary to modulate your brake pedal
and accelerator to avoid spin-out. Ease the vehicle down
from the log with your brake.
4-26

Driving Uphill
Once you decide you can safely drive up the hill, you
need to take some special steps:
Use transmission and transfer case low gear and
get a rm grip on the steering wheel.
Get a smooth start up the hill and try to maintain
your speed. Do not use more power than you
need, because you do not want your wheels to start
spinning or sliding.
Let the traction system work to control any wheel
slippage. The traction control system allows for
moderate wheel spin with some capability to dig in
and power up the hill.
Do not continue if the vehicle shudders or exhibits
suspension hopping. This can cause damage to
the driveline or suspension components. Improper
driving technique is not covered by your vehicle
warranty.
Try to drive straight up the hill if at all possible. If
the path twists and turns, you might want to nd
another route.
{CAUTION:
Turning or driving across steep hills can be
dangerous. You could lose traction, slide
sideways, and possibly roll over. You could be
seriously injured or killed. When driving up
hills, always try to go straight up.
Ease up on your speed as you approach the top of
the hill.
Attach a ag to the vehicle to make you more
visible to approaching traffic on trails or hills.
Sound the horn as you approach the top of the hill
to let opposing traffic know you are there.
Use your headlamps even during the day. They
make you more visible to oncoming traffic.
4-28

{CAUTION:
Driving to the top (crest) of a hill at full speed
can cause an accident. There could be a
drop-off, embankment, cliff, or even another
vehicle. You could be seriously injured or
killed. As you near the top of a hill, slow down
and stay alert.
Q:What should I do if my vehicle stalls, or is about
to stall, and I cannot make it up the hill?
A:If this happens, there are some things you should
do, and there are some things you must not do.
First, here is what youshoulddo:
Push the brake pedal to stop the vehicle and keep it
from rolling backwards. Also, apply the parking
brake.
If your engine is still running, shift the transmission to
REVERSE (R), release the parking brake, and slowly
back down the hill in REVERSE (R).
If your engine has stopped running, you will need to
restart it. With the brake pedal pressed, apply the
parking brake. If you have an automatic
transmission, shift the transmission to PARK (P).Restart the engine. Then, shift to REVERSE (R),
release the parking brake, and slowly back down the
hill as straight as possible in REVERSE (R).
As you are backing down the hill, put your left hand
on the steering wheel at the 12 o’clock position. This
way, you will be able to tell if your wheels are straight
and maneuver as you back down. It is best that you
back down the hill with your wheels straight rather
than in the left or right direction. Turning the wheel
too far to the left or right will increase the possibility
of a rollover.
Here are some things youmust notdo if you stall, or
are about to stall, when going up a hill:
Never attempt to prevent a stall by shifting into
NEUTRAL (N) to rev-up the engine and regain
forward momentum. This will not work. Your vehicle
will roll backwards very quickly and you could go
out of control.
Instead, apply the regular brake to stop the vehicle.
Then apply the parking brake. Shift to
REVERSE (R), release the parking brake, and
slowly back straight down.
Never attempt to turn around if you are about to
stall when going up a hill. If the hill is steep
enough to stall your vehicle, it is steep enough to
cause you to roll over if you turn around. If you
cannot make it up the hill, you must back straight
down the hill.
4-29

Q:Suppose, after stalling, I try to back down the
hill and decide I just cannot do it. What should
I do?
A:Set the parking brake. If you have an automatic
transmission, shift to PARK (P). 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 PARK (P), or, if you have a
manual transmission, even if you are in gear.
CAUTION: (Continued)
CAUTION: (Continued)
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 PARK (P),
or, put the manual transmission in FIRST (1).
But do not shift the transfer case to NEUTRAL.
Leave the transfer case in the Four-Wheel
High, Four-Wheel-High Lock, or
Four-Wheel-Low Lock position.
4-30

Driving Downhill
When off-roading takes you downhill, you will want to
consider a number of things:
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, then try to
keep your vehicle headed straight down, and use a
low gear. This way, engine drag can help your brakes
and they will not have to do all the work. Descend
slowly, keeping your 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.
Q:Are there some things I should not do when
driving down a hill?
A:Yes! These are important because if you
ignore them you could lose control and have a
serious accident:
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that is not too
steep to drive down may be too steep to drive
across. You could roll over if you do not drive
straight down.
Never go downhill with the transmission in
NEUTRAL (N). This is called “free-wheeling.” Your
brakes will have to do all the work and could
overheat and fade.
Q:Am I likely to stall when going downhill?
A:It is much more likely to happen going uphill. But if
it happens going downhill, here is what to do:
1. Stop your vehicle by applying the regular brakes.
Apply the parking brake.
2. If you have an automatic transmission, shift to
PARK (P). 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.
4-31

If you drive regularly in steep country, or if you are
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. SeeOff-Road
Driving on page 4-17for information about driving
off-road.
Keep your vehicle in good shape. Check all uid
levels and also the brakes, tires, cooling system,
and transmission. These parts can work hard
on mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you go
down a steep or long hill.
{CAUTION:
If you do not shift down, your 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 your engine assist your brakes on a
steep downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have
to do all the work of slowing down. 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 your engine running and your vehicle in
gear when you go downhill.
Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your
engine and transmission, and you can climb the
hill better.
4-44

Whatever the condition — smooth ice, packed, blowing,
or loose snow — drive with caution.
The traction control system (TCS) improves your ability
to accelerate when driving on a slippery road. It will
improve your ability to accelerate. SeeIf Your Vehicle is
Stuck in Sand, Mud, Ice or Snow on page 4-50. Even
though your vehicle has TCS, you will want to slow down
and adjust your driving to the road conditions. Under
certain conditions, you may want to turn your traction
system off, such as when driving through deep
snow and loose gravel, to help maintain vehicle motion
at lower speeds. SeeTraction Control System (TCS)
on page 4-9andStabiliTrak
®System (Automatic
Transmission) on page 4-11.
Your anti-lock brake system (ABS) improve your
vehicle’s stability when you make a hard stop on a
slippery road. Even though you have ABS, you will wantto begin stopping sooner than you would on dry
pavement. SeeAnti-Lock Brake System (ABS) on
page 4-7.
Allow greater following distance on any
slippery road.
Watch for slippery spots. The road might be ne
until you hit a spot that is covered with ice. On
an otherwise clear road, ice patches may appear in
shaded areas where the sun cannot reach, such
as around clumps of trees, behind buildings,
or under bridges. Sometimes the surface of a curve
or an overpass may remain icy when the
surrounding roads are clear. If you see a patch of
ice ahead of you, brake before you are on it. Try not
to brake while you are actually on the ice, and
avoid sudden steering maneuvers.
4-47

If Your Vehicle is Stuck in Sand,
Mud, Ice or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you do not want to
spin your wheels too fast. The method known as rocking
can help you get out when you are stuck, but you
must use caution.
{CAUTION:
If you let your tires spin at high speed, they can
explode, and you or others could be injured.
And, the transmission or other parts of the
vehicle can overheat. That could cause an
engine compartment re or other damage.
When you are stuck, spin the wheels as little as
possible. Do not spin the wheels above 35 mph
(55 km/h) as shown on the speedometer.
Notice:Spinning your wheels can destroy parts of
your vehicle as well as the tires. If you spin the
wheels too fast while shifting your transmission
back and forth, you can destroy your transmission.
For more information about using tire chains on your
vehicle, seeTire Chains on page 5-71.
Rocking Your Vehicle to Get It Out
First, turn your steering wheel left and right. That
will clear the area around your front wheels. Your vehicle
has a traction control system that will activate when
the system senses that the wheels are spinning.
SeeTraction Control System (TCS) on page 4-9for
more information. Then, with the wheels straight ahead,
shift back and forth between REVERSE (R) and a
forward gear, or with a manual transmission, between
FIRST (1) or SECOND (2) and REVERSE (R), spinning
the wheels as little as possible. Release the accelerator
pedal while you shift, and press lightly on the
accelerator pedal when the transmission is in gear. By
slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that
may free your vehicle. If that does not get you out
after a few tries, you may need to be towed out. Or, you
can use your recovery loops. If you do need to be
towed out, seeTowing Your Vehicle on page 4-57.
4-50

Here are some important things to consider before you
do recreational vehicle towing:
What’s the towing capacity of the towing vehicle?
Be sure you read the tow vehicle manufacturer’s
recommendations.
How far will you tow? Some vehicles have
restrictions on how far and how long they can tow.
Do you have the proper towing equipment?
See your dealer or trailering professional for
additional advice and equipment recommendations.
Is your vehicle ready to be towed? Just as you
would prepare your vehicle for a long trip, you’ll
want to make sure your vehicle is prepared to be
towed. SeeBefore Leaving on a Long Trip on
page 4-42.
Dinghy Towing
Use the following procedure to tow your vehicle:
1. Shift the transmission to NEUTRAL (N).
2. Turn the engine off, but leave the ignition in ON.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the
tow vehicle.
{CAUTION:
Shifting an all-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the automatic transmission is in
PARK (P) or the manual transmission is in any
gear. You or others could be injured. Make
sure the parking brake is rmly set before you
shift the transfer case to NEUTRAL.
5. Shift the transfer case to NEUTRAL (N). See
All-Wheel Drive on page 2-22for the proper
procedure to select the NEUTRAL position for
your vehicle.
6. Put the transmission in PARK (P) for an automatic
transmission or in FIRST (1) for a manual
transmission.
7. Release the parking brake only after the
vehicle being towed is rmly attached to the
towing vehicle.
8. Turn the ignition off.
After towing, see “Shifting Out of NEUTRAL” under
All-Wheel Drive on page 2-22.
4-58