2003 GMC YUKON DENALI Owners Manual

Q: Am I likely to stall when going downhill?
A: It’s much more likely to happen going uphill. But if it
happens going downhill, here’s what
to do.
Stop your vehicle by applying the regular brakes.
Apply the parking brake.
Shift to PARK (P) and, while still braking, restart the
Shift back to a low gear, release the parking brake,
If the engine won’t start, get out and get help.
engine.
and
drive straight down.
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.
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 doesn’t mean you
have to drive it. The last vehicle to try it might have
rolled over.
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,.iving across an -_:line that’s too steep wili
make your vehicle roll over. You could be
seriously injured
or killed. If you have any
doubt about the steepness
of the incline, don’t
drive across
it. Find another route instead.
Q: What if I’m driving across an incline that’s 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.
Stalling on an Incline
If your vehicle stalls when you’re crossing an incline, be
sure
you (and your passengers) get out on the uphill
side, even if the door there is harder to open. If you get
out on the downhill side and the vehicle starts to roll
over, you’ll be right in its path.
If you have to walk down the slope, stay out of the path
the vehicle will take
if it does roll over.
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L

Driving in Water
Heavy rain can mean flash flooding, and flood waters
demand extreme caution.
Find out how deep the water
is before you drive through
it. If it’s deep enough to cover your wheel hubs, axles
or exhaust pipe, don’t try
it - you probably won’t
get through. Also, water that deep can damage your
axle and other vehicle parts.
If the water isn’t 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’ll 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.
I
- - - - -ng through rushing water can be
dangerous. Deep water can sweep your vehicle
downstream and you and your passengers
i could drown. If it’s only shallow water, it can
still wash away the ground from under your
tires, and you could lose traction and roll the
vehicle over. Don’t drive through rushing water.
I I
See Driving in Rain and on Wet Roads on page 4-29 for
more information on driving through water.
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 fire hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, 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. Refer
to the Maintenance Schedule
for additional information.
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Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely
to be
impaired
- by alcohol or drugs, with night vision
problems, or by fatigue. Here are some tips on
night driving.
Drive defensively.
0 Don't drink and drive.
Since you can't see as well, you may need to slow
down and keep more space between you and
other vehicles.
Slow down, especially on higher speed roads. Your
headlamps can light up only
so much road ahead.
In remote areas, watch for animals.
If you're tired, pull off the road in a safe place
and rest.
No one can see as well at night as in the daytime.
But as we get older these differences increase.
A 50-year-old driver may require at least twice as much
light to see the same thing at night as a 20-year-old.
What you do in the daytime can also affect your
night vision. For example,
if you spend the day in bright
sunshine you are wise
to wear sunglasses. Your
eyes will have less trouble adjusting to night. But
if
you're driving, don't wear sunglasses at night. They may
cut down on glare from headlamps, but they also
make a
lot of things invisible.
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You can be temporarily blinded by approaching
headlamps.
It can take a second or two, or even several
seconds, for your eyes
to readjust to the dark. When
you are faced with severe glare (as from a driver
who doesn’t lower the high beams, or a vehicle with
misaimed headlamps),
slow down a little. Avoid staring
directly into the approaching headlamps.
Keep your windshield and all the glass on your vehicle
clean
- inside and out. Glare at night is made much
worse by dirt on the glass. Even the inside of the glass
can build up a film caused by dust. Dirty glass makes
lights dazzle and flash more than clean glass would,
making the pupils of your eyes contract repeatedly.
Remember that your headlamps light up far less of a
roadway when you are in a turn or curve. Keep
your eyes moving; that way, it’s easier
to pick out dimly
lighted objects.
Just as your headlamps should be
checked regularly for proper aim,
so should your eyes
be examined regularly. Some drivers suffer from
night blindness
- the inability to see in dim light - and
aren’t even aware of it.
Driving in Rain and on Wet Roads
Rain and wet roads can mean driving trouble. On a wet
road, you can’t stop, accelerate or turn
as well
because your tire-to-road traction isn’t as good as on
dry roads. And,
if your tires don’t have much tread left,
you’ll get even less traction.
It’s always wise to go
slower and be cautious
if rain starts to fall while you are
driving. The surface may get wet suddenly when your
reflexes are tuned for driving on dry pavement.
4-29

The heavier the rain, the harder it is to see. Even if your
windshield wiper blades are in good shape, a heavy
rain can make it harder to see road signs and
traffic signals, pavement markings, the edge of the road
and even people walking.
It’s wise to keep your wiping equipment in good shape
and keep your windshield washer tank filled with
washer fluid. Replace your windshield wiper inserts
when they show signs of streaking or missing areas on
the windshield, or when strips of rubber start to
separate from the inserts. Driving too fast through large
water puddles or even
going through some car washes can cause problems,
too. The water may affect your brakes. Try to avoid
puddles. But
if you can’t, try to slow down before
you hit them.
Wet brakes can cause accidents. They won’t
work as well in a quick stop and may cause
pulling to one side. You could lose control
of
the vehicle.
After driving through a large puddle
of water
or a car wash, apply your brake pedal lightly
until your brakes work normally.
4-30

Hydroplaning
Hydroplaning is dangerous. So much water can build up
under your tires that they can actually ride on the
water. This can happen
if the road is wet enough and
you’re going fast enough. When your vehicle is
hydroplaning, it has little or no contact with the road.
Hydroplaning doesn’t happen often. But it can
if
your tires do not have much tread or if the pressure in
one or more is low. It can happen
if a lot of water is
standing on the road. If you can see reflections
from trees, telephone poles or other vehicles, and
raindrops “dimple” the water’s surface, there could be
hydroplaning.
Hydroplaning usually happens at higher speeds. There
just isn’t a hard and fast rule about hydroplaning.
The best advice is to slow down when
it is raining.
Driving Through Deep Standing Water
Notice: If you drive too quickly through deep
puddles or standing water, water can come
in
through your engine’s air intake and badly damage
your engine. Never drive through water that
is
slightly lower than the underbody of your vehicle. If
you can’t avoid deep puddles or standing water,
drive through them very slowly.
Drivhg Through Flowing Water
~~
I
Flowing or rushing water creates strong forces.
If you try to drive through flowing water, as you
might at a low water crossing, your vehicle can
be carried away.
As little as six inches of
flowing water can carry away a smaller vehicle.
If this happens, you and other vehicle
occupants could drown. Don’t ignore police
warning signs, and otherwise be very cautious
about trying to drive through flowing water.
Some Other Rainy Weather Tips
Turn on your low-beam headlamps - not just your
parking lamps
- to help make you more visible to
others.
* Besides slowing down, allow some extra following
distance. And be especially careful when you
pass another vehicle. Allow yourself more clear
room ahead, and be prepared to have your
view restricted by road spray.
* Have good tires with proper tread depth. See Tires
on page 5-55.
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