2011 GMC Sierra All Terrain HD Concept Design
The new 2011 Sierra HD underpins the All Terrain HD concept, with a modified, production-based 4WD chassis and the Duramax diesel/Allison 1000 six-speed powertrain. The enhanced suspension and unique body dimensions, including increased ground clearance and wider track, as well as greater approach/departure angles, deliver off-road capability while maintaining HD levels of payload and trailering capacity. The All Terrain HD is painted Iridium Metallic – a dark charcoal color that reveals a reddish, anodized inflection when viewed from certain angles.