2003 GMC YUKON DENALI Owners Manual

Operating Your All-Wheel-Drive
Vehicle
Off Paved Roads
Many of the same design features that help make your
vehicle responsive on paved roads during poor weather
conditions
- features like all-wheel drive - help make it
much better suited for off-road use than a conventional
passenger car.
Its higher ground clearance also helps
your vehicle step over some off-road obstacles. But your
vehicle doesn’t have features like special underbody
shielding and
a transfer case low gear range, things that
are usually thought necessary for extended or severe
off-road service. This guide is for operating your vehicle
off paved roads.
Also, see
Braking on page 4-6.
Off-road driving can be great fun. But it does have
some definite hazards. The greatest of these is
the terrain itself.
“Off-roading” 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.
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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Environmental Concerns
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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 Loading
Your Vehicle on page 4-44 and Tires
on page 5-55.
Off-road driving can provide wholesome and satisfying
recreation. However, it also raises environmental
concerns. we recognize these concerns and urge every
off-roader to follow these basic rules for protecting
the environment:
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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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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 u’re on an [-.7aved surface.
When ; u’re driving R-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.
4-1 8

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:
0 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 Drunken Driving
on page 4-2.
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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.
Ma ~ hills are simply ~- - -Lee, .or 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 things
to consider as you
approach a hill.
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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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Driving Uphill
Once you decide you can safely drive up the hill, you
need to take some special steps.
Use a low year and get a firm grip on the
steering wheel.
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.
Get a smooth start up the hill and try to maintain
0 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.
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. Driving to the top (crest)
of a hill
a, ,ull 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.
Q: What should I do if my vehicle stalls, or is
about to stall, and
I can’t make it up the hill?
A: If this happens, there are some things you should
do and there are some things you must not do. First, here’s what you
should do:
Push the brake pedal to stop the vehicle and keep
it from rolling backwards.
Also, apply the parking
brake.
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If your engine is still running, shift the transmission
to REVERSE (R), release the parking brake, and
slowly back down the hill as straight as possible in
REVERSE (R).
As you are backing down the hill, put your left hand
on the steering wheel at the
12 o’clock position.
This way, you’ll be able
to tell if your wheels
are straight and maneuver as you back down.
It’s best that you back down the hill with your wheels
straight rather than in the left or right direction.
Turning the wheel
too far to the left or right
will increase the possibility of a rollover.
Here are some things you
must not do if you stall, or
are about to stall, when going up a hill.
Never attempt to prevent a stall by shifting into
NEUTRAL (N)
to “rev-up” the engine and regain
forward momentum. This won’t work. Your vehicle
will roll backwards very quickly and you could
go out of control. Instead, apply the
regular brake to stop the vehicle.
Then apply the parking brake. Shift to
REVERSE
(R), release the parking brake, and
slowly back straight down.
Never attempt to turn around if you are about to
stall when going up a hill. If the hill is steep
enough to stall your vehicle, it’s steep enough
to
cause you to roll over if you turn around. If you can’t
make it up the hill, you must back straight down
the hill.
Q: Suppose, after stalling, I try to back down
the hill and decide
I just can’t do it. What
should
I do?
A: Set the parking brake, put your transmission in
PARK
(P) and turn off the engine. Leave the
vehicle and
go get some help. Exit on the uphill
side and stay clear of the path the vehicle would
take
if it rolled downhill.
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Driving Downhill
When off-roading takes you downhill, you’ll want to
consider a number of things:
How steep is the downhill? Will I be able to maintain
vehicle control?
0 What’s the surface like? Smooth? Rough? Slippery?
Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts? Logs?
Boulders?
What’s at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, then try to
keep your vehicle headed straight down, and use a
low gear. This way, engine drag can help your brakes
and they won’t have to do all the work. Descend slowly,
keeping your vehicle under control at all times.
Heavy braking when going down a hill can
cause your brakes to overheat and fade.
This could cause
loss of control and a serious
accident. Apply the brakes lightly when
descending a hill and use a
low gear to keep
vehicle speed under control.
0: Are there some things I should not do when
driving down a hill?
A: Yes! These are important because if you ignore
them you could lose control and have a serious
accident.
When driving downhill, avoid turns that take you
across the incline of the hill. A hill that’s not too
steep to drive down may be too steep to drive across. You could roll over
if you don’t drive
straight down.
Never go downhill with the transmission in
NEUTRAL (N). This is called “free-wheeling.”
Your brakes will have to
do all the work and could
overheat and fade.
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