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.
Not all the upgrades are on the outside. The All Terrain HD includes IntelliLink with Text Messaging Alerts and Siri Eyes Free for iPhone users, OnStar with 4G LTE, and a standard built-in Wi-Fi hotspot. The hotspot is active whenever the vehicle is on and comes with a three-month/three-gigabyte data trial. The interior features a carbon fiber-inspired theme with the ALL TERRAIN logo on the instrument cluster and a standard rearview camera system. 2015 Sierra HD models also offer safety features such as forward collision alert, lane departure warning with an active safety seat, and front and rear park assist. Head-curtain and seat-mounted side airbags are standard on the 2500HD and available on 3500HD models. All models are backed by GMC Pro Grade Protection, and come with two years of scheduled maintenance (including diesel exhaust fluid), as well as a three-year/36,000-miles bumper-to-bumper warranty and a five-year/100,000-mile powertrain warranty.
The GMC Sierra All Terrain HD will go on sale this fall as a 2015 model.