Braking In Emergencies; Locking Rear Axle - GMC 2007 Yukon XL Owner's Manual

As you brake, your computer keeps receiving
updates on wheel speed and controls braking
pressure accordingly.
Remember: ABS does not change the time you
need to get your foot up to the brake pedal or
always decrease stopping distance. If you get too
close to the vehicle in front of you, you will not have
time to apply your brakes if that vehicle suddenly
slows or stops. Always leave enough room up
ahead to stop, even though you have ABS.
Using ABS
Do not pump the brakes. Just hold the brake
pedal down firmly and let anti-lock work for you.
You may feel the brakes vibrate, or you may notice
some noise, but this is normal.

Braking in Emergencies

With ABS, you can steer and brake at the same
time. In many emergencies, steering can help you
more than even the very best braking.

Locking Rear Axle

If your vehicle has this feature, your locking rear
axle can give you additional traction on snow, mud,
ice, sand or gravel. It works like a standard axle
most of the time, but when one of the rear wheels
has no traction and the other does, this feature will
allow the wheel with traction to move the vehicle.
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