traction control GMC C-SERIES 1999 Owners Manual

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2-36 Cruise Control (If Equipped)
With cruise control, you can
maintain a speed of about
30 mph (48 km/h) or more
without keeping your foot
on the accelerator. Cruise
control does not work at
speeds below about 30 mph
(48 km/h).
If you have an automatic transmission and you apply
your brakes, the cruise control will shut off.
If you have a manual transmission and you apply your
brakes or push the clutch pedal, the cruise control will
shut off.CAUTION:

Cruise control can be dangerous where you
can't drive safely at a steady speed. So,
don't use your cruise control on winding
roads or in heavy traffic.

Cruise control can be dangerous on
slippery roads. On such roads, fast changes
in tire traction can cause needless wheel
spinning, and you could lose control. Don't
use cruise control on slippery roads.
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2-41
Let up on the accelerator before you turn on your
inter
-axle differential lock. When you turn on this
control, the DIFF LOCK indicator on the instrument
panel will light.
NOTICE:
Activating the inter-axle differential lock when
the rear wheels are actually spinning freely, as
they might on ice or snow, can cause you to lose
control of the vehicle. It can also damage the
axles. Turn on this control only when the wheels
are not spinning freely.
Rear Axle Differential Lock Control
(If Equipped)
If your vehicle has a
Controlled Traction or
Locking Differential axle,
the control is located at the
lower right corner of the
instrument panel. You'll see
this control on single rear
axle vehicles.
If you're approaching a slippery surface where it looks
like one or even both wheels may start to slip, you can
use this control. It locks your rear differential so that
power is transmitted equally to both rear wheels.
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4-10 Steering Tips
Driving on Curves
It's important to take curves at a reasonable speed.
A lot of the ªdriver lost controlº accidents mentioned on
the news happen on curves. Here's why:
Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves. The
traction of the tires against the road surface makes it
possible for the vehicle to change its path when you turn
the front wheels. If there's no traction, inertia will keep
the vehicle going in the same direction. If you've ever
tried to steer a vehicle on wet ice, you'll understand this.
The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle
at which the curve is banked, and your speed. While
you're in a curve, speed is the one factor you
can control.
Suppose you're steering through a sharp curve. Then
you suddenly apply the brakes. Both control
systems
-- steering and braking -- have to do their
work where the tires meet the road. Unless you have
four
-wheel anti-lock brakes, adding the hard braking
can demand too much of those places. You can
lose control.The same thing can happen if you're steering through a
sharp curve and you suddenly accelerate. Those two
control systems
-- steering and acceleration -- can
overwhelm those places where the tires meet the road
and make you lose control.
What should you do if this ever happens? Ease up on the
brake or accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds are
based on good weather and road conditions. Under less
favorable conditions you'll want to go slower.
If you need to reduce your speed as you approach a
curve, do it before you enter the curve, while your front
wheels are straight ahead.
This is especially important with a tractor
-trailer. Try to
adjust your speed so you can ªdriveº through the curve.
Maintain a reasonable, steady speed. Wait to accelerate
until you are out of the curve, and then accelerate gently
into the straightaway.
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4-14
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
usually best handled by easing your foot off the
accelerator pedal.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). See ªDiesel Engine Exhaust Brakeº in the Index
for information about using the exhaust brake on
slippery surfaces. 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.
If you have the anti
-lock braking system, remember: It
helps avoid only the braking skid. If you do not have
anti
-lock, then in a braking skid (where the wheels are
no longer rolling), release enough pressure on the brakes
to get the wheels rolling again. This restores steering
control. Push the brake pedal down steadily when you
have to stop suddenly. As long as the wheels are rolling,
you will have steering control.
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6-20
Rear Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it.
See ªScheduled Maintenance Servicesº in the
Maintenance Schedule.
How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Maintenance Schedule.
Rear Axle Shift Motor (Option)
When to Check and Change Fluid
If you have an optional air-shift two-speed, controlled
traction, or locking differential type rear axle, a good
time to check the fluid level in the axle shift motor is
when the rear axle lubricant is checked. Use refrigerant
oil (shift motor only).
How to Check Fluid
Remove the plug on the front plate of the axle shift
motor, add enough fluid to raise the level to the bottom
of the filler plug hole, then replace the plug.
What to Use
Refer to your Maintenance Schedule to determine what
kind of lubricant to use.
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