Here’s a recap – with some additional photos – on the GMC Sierra All Terrain HD Concept, which will make its debut at the 2011 North American International Auto Show in Detroit. It’s shorter, wider and taller than the standard GMC Sierra pickup truck it is based on.

An “extreme truck” not unlike the Ford F-150 SVT Raptor, the Sierra AT HD Concept is fortified with heavy-duty hardware such as Fox off-road shocks, custom control arms, all round jounce shocks, automatic locking differentials and a front stabiliser bar with electric disconnection. It wears 35-inch BFGoodrich KM2 tyres that wrap 20-inch aluminum wheels.

It looks like a beast, and has the heart to match. Under that double vented hood lies a Duramax 6.6-litre V8 diesel producing 397 hp and 1,037 Nm of torque. Payload capacity is estimated at 1,225 kg (2,700 pounds) while towing capacity is rated at 5,896 kg or 13,000 pounds.

Gallery after the jump. Chevrolet Captiva owners, does the steering wheel look familiar?

[zenphotopress number=999 album=1847]