1999 GMC ENVOY Owners Manual

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4-13

Check your mirrors, glance over your shoulder and
start your left lane change signal before moving out
of the right lane to pass. When you are far enough
ahead of the passed vehicle to see its front in your
inside mirror, activate your right lane change signal
and move back into the right lane. (Remember that
your right outside mirror is convex. The vehicle you
just passed may seem to be farther away from you
than it really is.)

Try not to pass more than one vehicle at a time
on two
-lane roads. Reconsider before passing the
next vehicle.

Don't overtake a slowly moving vehicle too rapidly.
Even though the brake lamps are not flashing, it may
be slowing down or starting to turn.

If you're being passed, make it easy for the
following driver to get ahead of you. Perhaps you
can ease a little to the right.
Loss of Control
Let's review what driving experts say about what
happens when the three control systems (brakes, steering
and acceleration) don't have enough friction where the
tires meet the road to do what the driver has asked.
In any emergency, don't give up. Keep trying to steer
and constantly seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking reasonable
care suited to existing conditions, and by not
ªoverdrivingº those conditions. But skids are
always possible.
The three types of skids correspond to your vehicle's
three control systems. In the braking skid, your wheels
aren't rolling. In the steering or cornering skid, too
much speed or steering in a curve causes tires to slip and
lose cornering force. And in the acceleration skid, too
much throttle causes the driving wheels to spin.
A cornering skid and an acceleration skid are best
handled by easing your foot off the accelerator pedal.
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4-14
If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want the
vehicle to go. If you start steering quickly enough, your
vehicle may straighten out. Always be ready for a
second skid if it occurs.
Of course, traction is reduced when water, snow, ice,
gravel or other material is on the road. For safety, you'll
want to slow down and adjust your driving to these
conditions. It is important to slow down on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
While driving on a surface with reduced traction, try
your best to avoid sudden steering, acceleration or
braking (including engine braking by shifting to a lower
gear). Any sudden changes could cause the tires to slide.
You may not realize the surface is slippery until your
vehicle is skidding. Learn to recognize warning
clues
-- such as enough water, ice or packed snow on
the road to make a ªmirrored surfaceº
-- and slow down
when you have any doubt.
Remember: Any anti
-lock brake system (ABS) helps
avoid only the braking skid.
Driving Guidelines
This multipurpose passenger vehicle is defined as a
utility vehicle in Consumer Information Regulations
issued by the National Highway Traffic Safety
Administration (NHTSA) of the United States
Department of Transportation. Utility vehicles have
higher ground clearance and a narrower track to make
them capable of performing in a wide variety of off
-road
applications. Specific design characteristics give them a
higher center of gravity than ordinary cars. An
advantage of the higher ground clearance is a better
view of the road allowing you to anticipate problems.
They are not designed for cornering at the same speeds
as conventional two
-wheel-drive vehicles any more than
low
-slung sports cars are designed to perform
satisfactorily under off
-road conditions. If at all
possible, avoid sharp turns or abrupt maneuvers. As with
other vehicles of this type, failure to operate this vehicle
correctly may result in loss of control or
vehicle rollover.
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4-15
Off-Road Driving with Your
Four
-Wheel-Drive Vehicle
Also, see ªAnti-Lock Brakesº in the Index.
Off
-road driving can be great fun. But it does have some
definite hazards. The greatest of these is the
terrain itself.
ªOff
-roadingº means you've left the great North
American road system behind. Traffic lanes aren't
marked. Curves aren't banked. There are no road signs.
Surfaces can be slippery, rough, uphill or downhill. In
short, you've gone right back to nature.
Off
-road driving involves some new skills. And that's
why it's very important that you read this guide. You'll
find many driving tips and suggestions. These will help
make your off
-road driving safer and more enjoyable.
Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance and
service work done. Check to make sure all underbody
shields (if so equipped) are properly attached. Be sure
you read all the information about your
four
-wheel-drive vehicle in this manual. Is there enough
fuel? Is the spare tire fully inflated? Are the fluid levels
up where they should be? What are the local laws that
apply to off
-roading where you'll be driving? If you
don't know, you should check with law enforcement
people in the area. Will you be on someone's private
land? If so, be sure to get the necessary permission.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about
how to load your vehicle.

The heaviest things should be on the load floor and
forward of your rear axle. Put heavier items as far
forward as you can.

Be sure the load is secured properly, so driving on
the off
-road terrain doesn't toss things around.
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CAUTION:

Cargo on the load floor piled higher than
the seatbacks can be thrown forward
during a sudden stop. You or your
passengers could be injured. Keep cargo
below the top of the seatbacks.

Unsecured cargo on the load floor can be
tossed about when driving over rough
terrain. You or your passengers can be
struck by flying objects. Secure the
cargo properly.

Heavy loads on the roof raise the vehicle's
center of gravity, making it more likely to
roll over. You can be seriously or fatally
injured if the vehicle rolls over. Put heavy
loads inside the cargo area, not on the roof.
Keep cargo in the cargo area as far forward
and low as possible.
You'll find other important information in this manual.
See ªVehicle Loading,º ªLuggage Carrierº and ªTiresº
in the Index.
Environmental Concerns
Off-road driving can provide wholesome and satisfying
recreation. However, it also raises environmental
concerns. GM recognizes these concerns and urges
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, flowers, 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 fires (where permitted),
camp stoves and lanterns.

Never park your vehicle over dry grass or other
combustible materials that could catch fire from the
heat of the vehicle's exhaust system.
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4-17 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's 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'll want to know how to
use it properly.
Getting Familiar with Off-Road Driving
It's a good idea to practice in an area that's safe and
close to home before you go into the wilderness.
Off
-road driving does require some new and different
driving skills. Here's 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'll 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'll need more distance for braking, especially
since you're on an unpaved surface.
CAUTION:
When you're 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're driving on
or off the road, you and your passengers should
wear safety belts.
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4-18 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're 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's
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
firm grip on the steering wheel. Ruts, troughs or other
surface features can jerk the wheel out of your hands if
you're not prepared.
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 can't control the vehicle as
well or at all.
Because you will be on an unpaved surface, it's
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 isn't.
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 reflexes, 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.
See ªDrunken Drivingº in the Index.
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4-19 Driving on Off-Road 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 your vehicle can and can't do.
There are some hills that simply can't 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 can't 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, don't drive the hill.
Approaching a Hill
When you approach a hill, you need to decide if it's one
of those hills that's just 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 may
not see this because the crest of the hill is hidden by
bushes, grass or shrubs.
Here are some other things to consider 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
won't have to make turning maneuvers?

Are there obstructions on the hill that can block your
path (boulders, trees, logs or ruts)?

What's beyond the hill? Is there a cliff, an
embankment, a drop
-off, a fence? Get out and walk
the hill if you don't know. It's the smart way to
find 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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4-20 Driving Uphill
Once you decide you can safely drive up the hill, you
need to take some special steps.

Use a low gear and get a firm grip on the
steering wheel.

Get a smooth start up the hill and try to maintain
your speed. Don't use more power than you need,
because you don't want your wheels to start spinning
or sliding.

Try to drive straight up the hill if at all possible. If
the path twists and turns, you might want to find
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 flag to the vehicle to make you 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're there.

Use your headlamps even during the day. They make
you more visible to oncoming traffic.
CAUTION:
Driving to the top (crest) of a hill at full speed can
cause an accident. There could be a drop
-off,
embankment, cliff, or even another vehicle. You
could be seriously injured or killed. As you near
the top of a hill, slow down and stay alert.
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