2009 GMC Savana Van Owner's Manual - Page 210

Locking Rear Axle Vehicles with a locking rear axle can give more traction on snow, mud, ice, sand or gravel. It works like a standard axle most of the time, but when traction is low, this feature will allow the rear wheel with the most traction to move the vehicle. Steering Power Steering If power steering assist is lost because the engine stops or the system is not functioning, the vehicle can be steered but it will take more effort. All-Wheel Drive (AWD) System If the vehicle has this feature, engine power is sent to all four wheels when extra traction is needed. This is like four-wheel drive, but there is no separate lever or switch to engage or disengage the front axle. It is fully automatic, and adjusts itself as needed for road conditions. Steering Tips It is important to take curves at a reasonable speed. Traction in a curve depends on the condition of the tires and the road surface, the angle at which the curve is banked, and vehicle speed. While in a curve, speed is the one factor that can be controlled. If there is a need to reduce speed, do it before entering the curve, while the front wheels are straight. Try to adjust the speed so you can drive through the curve. Maintain a reasonable, steady speed. Wait to accelerate until out of the curve, and then accelerate gently into the straightaway. 4-8