wheel HUMMER H3 2007 Workshop Manual

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.
Driving Across an Incline
Sooner or later, an off-road trail will probably go
across the incline of a hill. If this happens,
you have to decide whether to try to drive across
the incline. Here are some things to consider:
A hill that can be driven straight up or down
may be too steep to drive across. When you
go straight up or down a hill, the length of the
wheel base — the distance from the front
wheels to the rear wheels — reduces the
likelihood the vehicle will tumble end over end.
But when you drive across an incline, the much
more narrow track width — the distance
between the left and right wheels — may not
prevent the vehicle from tilting and rolling over.
Also, driving across an incline puts more weight
on the downhill wheels. This could cause a
downhill slide or a rollover.
266

Surface conditions can be a problem when
you drive across a hill. Loose gravel, muddy
spots, or even wet grass can cause your tires
to slip sideways, downhill. If the vehicle slips
sideways, it can hit something that will
trip it — a rock, a rut, etc. — and roll over.
Hidden obstacles can make the steepness of
the incline even worse. If you drive across a
rock with the uphill wheels, or if the downhill
wheels drop into a rut or depression, your
vehicle can tilt even more.
For reasons like these, you need to decide
carefully whether to try to drive across an incline.
Just because the trail goes across the incline
does not mean you have to drive it. The last
vehicle to try it might have rolled over.
{CAUTION:
Driving across an incline that is too
steep will make your vehicle roll over.
You could be seriously injured or killed.
If you have any doubt about the
steepness of the incline, do not drive
across it. Find another route instead.
Q:What if I am driving across an incline
that is not too steep, but I hit some
loose gravel and start to slide downhill.
What should I do?
A:If you feel your vehicle starting to slide
sideways, turn downhill. This should help
straighten out the vehicle and prevent the side
slipping. However, a much better way to
prevent this is to get out and “walk the course”
so you know what the surface is like before
you drive it.
267

Driving in Mud, Sand, Snow, or Ice
When you drive in mud, snow, or sand, your wheels
will not get good traction. You cannot accelerate as
quickly, turning is more difficult, and you will need
longer braking distances.
It is best to use a low gear when you are in
mud — the deeper the mud, the lower the gear.
In really deep mud, the idea is to keep your vehicle
moving so you do not get stuck. Be careful to
keep mud from building up and washing onto the
engine cooling system.
When you drive on sand, you will sense a change
in wheel traction. But it will depend upon how
loosely packed the sand is. On loosely packed
sand, such as on beaches or sand dunes,
your tires will tend to sink into the sand. This has
an effect on steering, accelerating, and braking.
Drive at a reduced speed and avoid sharp turns
or abrupt maneuvers.Hard packed snow and ice offer the worst tire
traction. On these surfaces, it is very easy to lose
control. On wet ice, for example, the traction is
so poor that you will have difficulty accelerating.
And if you do get moving, poor steering and
difficult braking can cause you to slide out of
control.
{CAUTION:
Driving on frozen lakes, ponds, or rivers
can be dangerous. Underwater springs,
currents under the ice, or sudden thaws
can weaken the ice. Your vehicle could
fall through the ice and you and your
passengers could drown. Drive your
vehicle on safe surfaces only.
269

Driving in Water
Heavy rain can mean ash ooding, and ood
waters demand extreme caution.
Find out how deep the water is before you drive
through it. If it is deep enough to cover your wheel
hubs, axles, or exhaust pipe, do not try it — you
probably will not get through. Also, water that deep
can damage your axle and other vehicle parts.
Your vehicle is capable of depths up to 20 inches.
Know how to judge whether the water is deeper
than this before proceeding into it.
If the water is not too deep, drive slowly through it.
At faster speeds, water splashes on your ignition
system and your vehicle can stall. Stalling can also
occur if you get your tailpipe under water. And,
as long as your tailpipe is under water, you
will never be able to start your engine. When you
go through water, remember that when your
brakes get wet, it may take you longer to stop.{CAUTION:
Driving through rushing water can be
dangerous. Deep water can sweep your
vehicle downstream and you and your
passengers could drown. If it is only
shallow water, it can still wash away the
ground from under your tires, and you
could lose traction and roll the vehicle
over. Do not drive through rushing water.
SeeDriving in Rain and on Wet Roads on page 273
for more information on driving through water.
270

After Off-Road Driving
Remove any brush or debris that has collected
on the underbody, chassis, or under the hood.
These accumulations can be a re hazard.
After operation in mud or sand, have the brake
linings cleaned and checked. These substances
can cause glazing and uneven braking. Check
the engine and oil coolers for mud accumulation.
Thoroughly and carefully clean these devices
to allow proper cooling. Check the body structure,
steering, suspension, underbody shields,
wheels, tires, and exhaust system for damage.
Also, check the fuel lines and cooling system
for any leakage.
Your vehicle will require more frequent service
due to off-road use. See the Maintenance
Schedule for additional information.
Assist Steps
Your vehicle may be equipped with removable
side steps.
Remove the steps prior to off-roading to give your
vehicle more ground clearance and to prevent
damage to the vehicle from the side steps
dragging and/or catching on obstacles.
Notice:Do not drive off-road with the side
steps attached to your vehicle. You can damage
the side steps and/or your vehicle’s frame if
they get caught or drag against an obstacle.
This damage would not be covered by your
vehicle’s warranty. Always remove the side
steps prior to any off-road driving.
271

Highway Hypnosis
Is there actually such a condition as highway
hypnosis? Or is it just plain falling asleep at the
wheel? Call it highway hypnosis, lack of
awareness, or whatever.
There is something about an easy stretch of road
with the same scenery, along with the hum of the
tires on the road, the drone of the engine, and the
rush of the wind against the vehicle that can make
you sleepy. Do not let it happen to you! If it does,
your vehicle can leave the road in less than a
second, and you could crash and be injured.
What can you do about highway hypnosis?
First, be aware that it can happen.
Then here are some tips:
Make sure your vehicle is well ventilated,
with a comfortably cool interior.
Keep your eyes moving. Scan the road
ahead and to the sides. Check your mirrors
and your instruments frequently.
If you get sleepy, pull off the road into a rest,
service, or parking area and take a nap, get
some exercise, or both. For safety, treat
drowsiness on the highway as an emergency.
Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in at or rolling terrain.
279

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 vehicle’s 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 the wheels can destroy
parts of your vehicle as well as the tires.
If you spin the wheels too fast while shifting
the transmission back and forth, you can
destroy the transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 389.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right.
That will clear the area around the 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 241for 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.
286

By slowly spinning the wheels in the forward
and reverse directions, you will cause a rocking
motion that may free your vehicle. If that does
not get your vehicle out after a few tries, it
may need to be towed out. Or, you can use the
recovery loops. If your vehicle does need to
be towed out, seeTowing Your Vehicle
on page 294.
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.
Your vehicle has
two recovery loops
at the front of the
vehicle and one at the
rear of the vehicle.
You may need to use them if you are stuck
off-road and need to be pulled to some place
where you can continue driving.Rear of Vehicle
287

Recreational Vehicle Towing
Recreational vehicle towing means towing your
vehicle behind another vehicle — such as behind
a motorhome. The two most common types of
recreational vehicle towing are known as “dinghy
towing” (towing your vehicle with all four wheels
on the ground) and “dolly towing” (towing
your vehicle with two wheels on the ground and
two wheels up on a device known as a “dolly”).
With the proper preparation and equipment,
many vehicles can be towed in these ways. See
“Dinghy Towing” and “Dolly Towing,” following.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 278.
295

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 a full-time four-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
Full-Time Four-Wheel Drive on page 111for
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”
underFull-Time Four-Wheel Drive on page 111.
Dolly Towing
Notice:Dolly towing your vehicle will damage
drivetrain components. Do not dolly tow
your vehicle.
Your vehicle cannot be dolly towed. If you must
tow your vehicle behind another, use the
dinghy towing procedure listed previously.
296