The Sierra All Terrain HD package is available on 2500HD and 3500HD double cab and crew cab models, and is offered in SLE or SLT trims. The Sierra HD comes standard with the 6.0l gas engine while the Duramax turbo-diesel is available as an option. All models feature 4WD with an electronically controlled transfer case. You also get the Z71 Off Road package, which includes Rancho twin-tube shocks, hill descent control, and a skid plate.
Exterior upgrades include a chrome surround on the grille, exterior graphics, aluminum underbody shields, and unique 18-inch six-spoke chrome cast-aluminum wheels. The 2500HD is available with twenty-inch chrome aluminum wheels while the 3500HD model includes adjustable outside camper mirrors. The All Terrain HD package also includes LED signature headlamps, body-color bumpers (with chrome bumpers available), chrome mirrors covers and body side moldings, and a chrome front-lower bumper plate.
All Sierra HD models offer a CornerStep rear bumper, EZ Lift and Lower tailgate with lock, and StabiliTrak with Trailer Sway Control. HD models also get integrated cruise control, auto grade braking and diesel exhaust braking, as well as new Duralife brake rotors with up to double the service life. The trucks also offer enhanced cooling airflow, allowing both the 6.0l gasoline engine and the Duramax diesel to better maintain full power, especially under heavy loads or high ambient temperatures.