ESP GMC SIERRA 2001 Owner's Guide

4-22 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.

4-32
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.

Don't drink and drive.

Adjust your inside rearview mirror to reduce the
glare from headlamps behind you.

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.

4-35
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 ªdimpleº 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.
Driving Through Flowing Water
CAUTION:
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 the 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 ªTiresº in the Index.

4-44
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.

4-73 Safety Chains
You should always attach chains between your vehicle
and your trailer. Cross the safety chains under the
tongue of the trailer to help prevent the tongue from
contacting the road if it becomes separated from the
hitch. Instructions about safety chains may be provided
by the hitch manufacturer or by the trailer manufacturer.
For trailers up to 5,000 lbs. (2 270 kg) you may
attach the safety chains to the attaching points on the
bumper. For heavier trailers, follow the trailer or hitch
manufacturer's recommendation for attaching safety
chains. Always leave just enough slack so you can
turn with your rig. Never allow safety chains to drag
on the ground.
Trailer Brakes
If your trailer weighs more than 2,000 lbs. (900 kg)
loaded, then it needs its own brakes
-- and they must be
adequate. Be sure to read and follow the instructions for
the trailer brakes so you'll be able to install, adjust and
maintain them properly.Your trailer brake system can tap into the vehicle's
hydraulic brake system only if:

The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.

The trailer's brake system will use less than
0.02 cubic inch (0.3 cc) of fluid from your vehicle's
master cylinder. Otherwise, both braking systems
won't work well. You could even lose your brakes.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the fluid to
the rear brakes. But don't use copper tubing for this.
If you do, it will bend and finally break off. Use steel
brake tubing.
Driving with a Trailer
Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you'll want to
get to know your rig. Acquaint yourself with the feel
of handling and braking with the added weight of the
trailer. And always keep in mind that the vehicle you
are driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.

4-77 When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

Start your engine;

Shift into a gear; and

Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for
more on this. Things that are especially important
in trailer operation are automatic transmission fluid
(don't overfill), engine oil, axle lubricant, belt, cooling
system and brake system. Each of these is covered in
this manual, and the Index will help you find them
quickly. If you're trailering, it's a good idea to review
these sections before you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
Trailer Wiring Harness
Your vehicle is equipped with one of the following
wiring harnesses for towing a trailer or hauling a
slide
-in camper.
Basic Trailer Wiring Package
All regular, extended cab crew cab pickups have a
six
-wire trailer towing harness.
The six-wire harness is located at the rear of the vehicle
and is tied to the vehicle's frame. The harness requires
the installation of a trailer
-wiring harness connector,
which is available through your dealer.

5-18
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing and/or high outside temperatures, the fan speed
increases as the clutch more fully engages. So you may
hear an increase in fan noise. This is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is merely the cooling system functioning
properly. The fan will slow down when additional
cooling is not required and the clutch disengages.
You may also hear this fan noise when you start
the engine. It will go away as the fan clutch
partially disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a
few tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off
the accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in
a skid. In any rear blowout, remove your foot from
the accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.

6-22 How to Check
Because this operation can be a little difficult,
you may choose to have this done at the dealership
service department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Be sure to get an accurate reading if you check
your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.
In heavy traffic
-- especially in hot weather.

While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180F to 200F
(82C to 93C).
Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are above
50F (10C). If it's colder than 50F (10C), drive
the vehicle in THIRD (3) until the engine temperature
gage moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine run
at idle for five minutes if outside temperatures are
50F (10C) or more. If it's colder than 50F (10C),
you may have to idle the engine longer. Should the fluid
level be low during this cold check, you must check the
fluid hot before adding fluid. Checking the fluid hot will
give you a more accurate reading of the fluid level.

6-24
2. Push it back in all the way, wait three seconds and
then pull it back out again.
3. Check both sides of the dipstick, and read the lower
level. The fluid level must be in the COLD area,
below the cross
-hatched area, for a cold check or in
the HOT area or cross
-hatched area for a hot check.
4. If the fluid level is in the acceptable range, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
How to Add Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission fluid to use. See ªRecommended
Fluids and Lubricantsº in the Index.
Add fluid only after checking the transmission fluid while
it is hot. (A cold check is used only as a reference.)
If the fluid level is low, add only enough of the proper
fluid to bring the level up to the HOT area for a hot
check. It doesn't take much fluid, generally less than
one pint (0.5 L). Don't overfill.
NOTICE:
We recommend you use only fluid labeled
DEXRON-III, because fluid with that label is
made especially for your automatic transmission.
Damage caused by fluid other than DEXRON
-III
is not covered by your new vehicle warranty.

After adding fluid, recheck the fluid level as
described under ªHow to Check.º

When the correct fluid level is obtained, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.

6-25
Automatic Transmission Fluid
(Allison Only)
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 25,000 miles
(41 500 km) if the vehicle is mainly driven under one
or more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these conditions,
change the fluid and filter every 50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.
How to Check
Because this operation can be a little difficult, you
may choose to have this done at the dealership
service department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Be sure to get an accurate reading if you check
your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.