2003 Chevrolet Express Van Owner's Manual - Page 205

Using Anti-Lock Don't pump the brakes. Just hold the brake pedal down firmly and let anti-lock work for you. You may feel the brakes vibrate, or vou mav notice some noise, but Locking Rear Axle If your vehicle has-thisfeature, 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. As you brake, your computer keeps receiving updates on wheel speed and controls braking pressure accordingly. Remember: Anti-lock doesn't 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 won't 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 anti-lock brakes. 4-8