GMC TopKick 2007 Owner's Manual page 229

If you have a four-wheel-drive vehicle, shift into
4HI. See Four-Wheel Drive on page 117.
If you have the Traction Control System (TCS),
it will improve your ability to accelerate when
driving on a slippery road. But you can turn the
TCS off if you ever need to. You should turn
the system off if your vehicle ever gets stuck in
sand, mud, ice, or snow. See If Your Vehicle
is Stuck in Sand, Mud, Ice, or Snow on page 232.
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 the TCS off, such as when driving
through deep snow and loose gravel, to help
maintain vehicle motion at lower speeds. See
Traction Control System (TCS) on page 212.
If you do not have TCS, accelerate gently. Try not
to break the fragile traction. If you accelerate
too fast, the drive wheels will spin and polish the
surface under the tires even more.
Unless you have the Anti-Lock Brake System
(ABS), you will want to brake very gently, too.
If you do have ABS, see Anti-Lock Brake System
(ABS) on page 208. ABS improves your vehicle's
stability when you make a hard stop on a
slippery road. Whether you have ABS or not,
you will want to begin stopping sooner than you
would on dry pavement. Without ABS, if you
feel your vehicle begin to slide, let up on
the brakes a little. Push the brake pedal down
steadily to get the most traction you can.
Remember, unless you have ABS, if you brake so
hard that your wheels stop rolling, you will just
slide. Brake so your wheels always keep rolling
and you can still steer.
•
Whatever your braking system, allow greater
following distance on any slippery road.
•
Watch for slippery spots. The road might be
fine 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.
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