wheel HUMMER H3 2007 Service Manual

Environmental Concerns
Off-road driving can provide wholesome and
satisfying recreation. However, it also raises
environmental concerns. We recognize these
concerns and urge every off-roader to follow
these basic rules for protecting the environment:
Always use established trails, roads, and
areas that have been specially set aside
for public off-road recreational driving; obey
all posted regulations.
Avoid any driving practice that could damage
the environment — shrubs, owers, trees,
grasses — or disturb wildlife. This includes
wheel-spinning, breaking down trees, or
unnecessary driving through streams or over
soft ground.
Always carry a litter bag — make sure all
refuse is removed from any campsite
before leaving.
Take extreme care with open res (where
permitted), camp stoves, and lanterns.
Never park your vehicle over dry grass or
other combustible materials that could
catch re from the heat of the vehicle’s
exhaust system.
Traveling to Remote Areas
It makes sense to plan your trip, especially when
going to a remote area. Know the terrain and
plan your route. You are much less likely to
get bad surprises. Get accurate maps of trails
and terrain. Try to learn of any blocked or
closed roads.
It is also a good idea to travel with at least one
other vehicle. If something happens to one
of them, the other can help quickly.
Does your vehicle have a winch? If so, be sure
to read the winch instructions. In a remote area,
a winch can be handy if you get stuck. But you
will want to know how to use it properly.
High Mobility Characteristics
The HUMMER H3 has a 10 inch (25.4 cm)
running ground clearance (A) and a 9 inch
(22.8 cm) axle to ground clearance (B) while
maintaining a low silhouette and a low center
of gravity.
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Your vehicle can climb a 16 inch (40.6 cm) vertical
step. Step climbing is best done by approaching
the step at an angle rather than straight on.
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 FIRST (1) gear,
Four-Wheel-Low 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 will not operate
if the brakes are applied, even slightly.
4. If wheel spin cannot be controlled by the
system, fully press the brake pedal with
your left foot so all wheel spin is halted.
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.
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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:
Four-Wheel High position for higher speeds
and Four-Wheel-Low Lock for more torque and
lower speeds. Transmission FIRST (1) 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.
Getting Familiar with Off-Road Driving
It is a good idea to practice in an area that is
safe and close to home before you go into
the wilderness. Off-road driving does require some
new and different skills. Here is what we mean.
Tune your senses to different kinds of signals.
Your eyes, for example, need to constantly sweep
the terrain for unexpected obstacles. Your ears
need to listen for unusual tire or engine sounds.
With your arms, hands, feet and body, you will
need to respond to vibrations and vehicle bounce.
Controlling your vehicle is the key to successful
off-road driving. One of the best ways to control
your vehicle is to control your speed. Here are
some things to keep in mind. At higher speeds:
You approach things faster and you have
less time to scan the terrain for obstacles.
You have less time to react.
You have more vehicle bounce when you
drive over obstacles.
You will need more distance for braking,
especially since you are on an unpaved
surface.
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{CAUTION:
When you are driving off-road, bouncing
and quick changes in direction can easily
throw you out of position. This could cause
you to lose control and crash. So, whether
you are driving on or off the road, you and
your passengers should wear safety belts.
Scanning the Terrain
Off-road driving can take you over many different
kinds of terrain. You need to be familiar with
the terrain and its many different features.
Here are some things to consider.
Surface Conditions:Off-roading can take you
over hard-packed dirt, gravel, rocks, grass, sand,
mud, snow, or ice. Each of these surfaces affects
the steering, acceleration, and braking of your
vehicle in different ways. Depending upon the kind
of surface you are on, you may experience slipping,
sliding, wheel spinning, delayed acceleration,
poor traction, and longer braking distances.Surface Obstacles:Unseen or hidden obstacles
can be hazardous. A rock, log, hole, rut, or bump
can startle you if you are not prepared for them.
Often these obstacles are hidden by grass, bushes,
snow, or even the rise and fall of the terrain itself.
Here are some things to consider:
Is the path ahead clear?
Will the surface texture change abruptly
up ahead?
Does the travel take you uphill or downhill?
There is more discussion of these subjects
later.
Will you have to stop suddenly or change
direction quickly?
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.
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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 235.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.
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Roll Your Tires Over Large Rocks
Do not straddle large
rocks; drive over them,
letting the tire cover
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.
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.
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What is beyond the hill? Is there a cliff, an
embankment, a drop-off, a fence? Get out and
walk the hill if you do not know. It is the smart
way to nd out.
Is the hill simply too rough? Steep hills often
have ruts, gullies, troughs, and exposed rocks
because they are more susceptible to the
effects of erosion.
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.
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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.
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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. This is because the NEUTRAL
position on the transfer case overrides
the transmission. You or someone else
CAUTION: (Continued)
CAUTION: (Continued)
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.
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?
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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.
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