See also:

Overview
The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain ...

Automatic Transmission
The automatic transmission has a shift lever located on the console between the seats. P (Park): This position locks the front wheels. It is the best position to use when starting the engine becaus ...

Tow/Haul Mode
(Tow/Haul): The vehicle may have a Tow/Haul mode. The button is located on the instrument panel under the climate controls. Push the button to activate the system. Push it again to deactivate the s ...