2003 GMC ENVOY Owner's Manual

Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in ¯at or rolling terrain.
If you drive regularly in steep country, or if you're
planning to visit there, here are some tips that can make
your trips safer and more enjoyable.See
Off-Road Driving with Your Four-Wheel-Drive
Vehicle on page 4-15for 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 don't shift down, your brakes could get
so hot that they wouldn't 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.
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{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 wouldn't 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.
·Stay in your own lane when driving on two-lane
roads in hills or mountains. Don't swing wide or
cut across the center of the road. Drive at speeds
that let you stay in your own lane.
·As you go over the top of a hill, be alert. There
could be something in your lane, like a stalled car or
an accident.
·You may see highway signs on mountains that
warn of special problems. Examples are long
grades, passing or no-passing zones, a falling rocks
area or winding roads. Be alert to these and take
appropriate action.
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Winter DrivingHere are some tips for winter driving:
·Have your vehicle in good shape for winter.
·You may want to put winter emergency supplies in
your vehicle.
Include an ice scraper, a small brush or broom, a
supply of windshield washer ¯uid, a rag, some winter
outer clothing, a small shovel, a ¯ashlight, a red
cloth and re¯ective warning triangles. And, if you will be
driving under severe conditions, include a small bag
of sand, a piece of old carpet or a couple of burlap bags
to help provide traction. Be sure you properly secure
these items in your vehicle.
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Driving on Snow or Ice
Most of the time, those places where your tires meet
the road probably have good traction.
However, if there is snow or ice between your tires and
the road, you can have a very slippery situation.
You'll have a lot less traction or ªgripº and will need to
be very careful.What's the worst time for this? ªWet ice.º Very cold
snow or ice can be slick and hard to drive on. But wet
ice can be even more trouble because it may offer
the least traction of all. You can get wet ice when it's
about freezing (32ÉF; 0ÉC) and freezing rain begins
to fall. Try to avoid driving on wet ice until salt and sand
crews can get there.
Whatever the condition ± smooth ice, packed, blowing
or loose snow ± drive with caution.
If you have traction assist, keep the system on. It will
improve your ability to accelerate when driving on
a slippery road. But you can turn the traction system off
if your vehicle ever gets stuck in sand, mud, ice or
snow. See
If You Are Stuck: In Sand, Mud, Ice or Snow
on page 4-44. Even though your vehicle has a traction
system, you'll want to slow down and adjust your
driving to the road conditions. See
Traction Assist
System (TAS) on page 4-8.
If you don't have a traction system, 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.
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Your anti-lock brakes improve your vehicle's stability
when you make a hard stop on a slippery road.
Even though you have an anti-lock braking system,
you'll want to begin stopping sooner than you would on
dry pavement. See
Braking on page 4-5.
·Allow greater following distance on any
slippery road.
·Watch for slippery spots. The road might be ®ne
until you hit a spot that's covered with ice. On
an otherwise clear road, ice patches may appear in
shaded areas where the sun can't reach: 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're actually on the ice, and avoid sudden
steering maneuvers.
If You're Caught in a Blizzard
If you are stopped by heavy snow, you could be in a
serious situation. You should probably stay with
your vehicle unless you know for sure that you are near
help and you can hike through the snow.
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Here are some things to do to summon help and keep
yourself and your passengers safe:
·Turn on your hazard ¯ashers.
·Tie a red cloth to your vehicle to alert police that
you've been stopped by the snow.
·Put on extra clothing or wrap a blanket around you.
If you have no blankets or extra clothing, make
body insulators from newspapers, burlap bags, rags,
¯oor mats ± anything you can wrap around
yourself or tuck under your clothing to keep warm.
You can run the engine to keep warm, but be careful.
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{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You can't see it or
smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle, especially any that is
blocking your exhaust pipe. And check around
again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will
help keep CO out.Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery charged. You will need a
well-charged battery to restart the vehicle, and possibly
for signaling later on with your headlamps. Let the
heater run for a while.
Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine
again and repeat this only when you feel really
uncomfortable from the cold. But do it as little as
possible. Preserve the fuel as long as you can. To help
keep warm, you can get out of the vehicle and do
some fairly vigorous exercises every half hour or so until
help comes.
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If You Are 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 don't want to spin your
wheels too fast. The method known as ªrockingº can
help you get out when you're 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're stuck, spin the wheels as little as
possible. Don't 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 information about using tire chains on your
vehicle, see
Tire Chains on page 5-62.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your front wheels. If you have a
four- wheel-drive vehicle, shift into 4HI. Then shift
back and forth between REVERSE (R) and a forward
gear, 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 doesn't get
you out after a few tries, you may need to be towed out.
If you do need to be towed out, see
Towing Your
Vehicle on page 4-45.
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