2009 HUMMER H2 Owners Manual

The vehicle has an approximate approach angle (A) of
42° and a departure angle (B) of 37°.
Design specications required a minimum gradeability of
60% (31°) slope, with the vehicle fully loaded, on high
friction surfaces at 6 mph (9.7 km/h). The vehicle is
expected to traverse this grade only for short durations.
Never stop and idle the vehicle or park it on this grade.
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The vehicle should be able to traverse a 40% (22°) side
slope at 6 mph (9.7 km/h) while fully loaded on high
friction surfaces.The 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.
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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.
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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-roading requires some new and different skills.
Tune your senses to different kinds of signals. Your eyes
need to constantly sweep the terrain for unexpected
obstacles. Your ears need to listen for unusual tire
or engine sounds. Use your arms, hands, feet, and body
to respond to vibrations and vehicle bounce.
Controlling the vehicle is the key to successful off-road
driving. One of the best ways to control the vehicle
is to control the speed. At higher speeds:
You approach things faster and have less time
to react.
There is less time to scan the terrain for obstacles.
The vehicle has more bounce when driving over
obstacles.
More braking distance is needed, especially on an
unpaved surface.
{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. Be familiar with the terrain and its many
different features.
Surface Conditions:Off-roading surfaces can be
hard-packed dirt, gravel, rocks, grass, sand, mud, snow,
or ice. Each of these surfaces affects the vehicle’s
steering, acceleration, and braking in different ways.
Depending on the surface, slipping, sliding, wheel
spinning, delayed acceleration, poor traction, and longer
braking distances can occur.
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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.
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?
Will you have to stop suddenly or change direction
quickly?
When driving 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.
When driving over bumps, rocks, or other obstacles, the
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.
Off-roading requires a different kind of alertness from
driving on paved roads and highways. There are no road
signs, posted speed limits, or signal lights. Use good
judgment about what is safe and what is not.
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° minimum
approach (A), 75° 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 The 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, the vehicle will cross logs
up to 10 inches (25.4 cm) in diameter. Approach the log
at approximately a 15° angle (A) with the transmission
in 1 (First) and the transfer case in 4LO LOCK and “walk”
the vehicle over, one tire at a time. It may be necessary to
modulate the brake pedal and accelerator to avoid
spin-out. Ease the vehicle down from the log with the
brake.
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Driving on Hills
Off-road driving often takes you up, down, or across a
hill. Driving safely on hills requires good judgment
and an understanding of what the vehicle can and
cannot do. There are some hills that simply cannot be
driven, no matter how well built the vehicle.
{CAUTION:
Many hills are simply too steep for any vehicle. If
you drive up them, you will stall. If you drive down
them, you cannot control your speed. If you drive
across them, you will roll over. You could be
seriously injured or killed. If you have any doubt
about the steepness, do not drive the hill.
Approaching a Hill
When you approach a hill, decide if it is too steep to
climb, descend, or cross. Steepness can be hard to
judge. On a very small hill, for example, there may be a
smooth, constant incline with only a small change in
elevation where you can easily see all the way to the top.
On a large hill, the incline may get steeper as you near
the top, but you might not see this because the crest of
the hill is hidden by bushes, grass, or shrubs.
Consider this as you approach a hill:
Is there a constant incline, or does the hill get
sharply steeper in places?
Is there good traction on the hillside, or will the
surface cause tire slipping?
Is there a straight path up or down the hill so you
will not have to make turning maneuvers?
Are there obstructions on the hill that can block your
path, such as boulders, trees, logs, or ruts?
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.
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Driving Uphill
Once you decide it is safe to drive up the hill:
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
speed. Not using more power than needed can
avoid spinning the wheels 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 the vehicle
warranty.
{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.
Try to drive straight up the hill if at all possible.
If the path twists and turns, you might want to
nd another route.
Ease up on the speed as you approach the top of
the hill.
Attach a ag to the vehicle to be 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 headlamps even during the day to make the
vehicle more visible to oncoming traffic.
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