NEW GMC Sierra All Terrain HD Truck Concept

Truck Concept GMC Sierra All Terrain HD The concept GMC previewed Thursday features a 39-degree approach angle and 31 degree departure angle. Built on an '11 Sierra 2500 crew cab body, with a 1500's five-foot, eight-inch box, the concept has a stock Duramax turbodiesel, making 390 horsepower and 745 pound-feet, like the production engine. Transmission also is stock, the Allison six-speed