The 2015 GMC Denali 2500HD is amazingly powerful pick up truck SUV. It has a Chevy twin brother named Chevrolet Silverado SS. First generation of Chevy Silverado and GMC Sierra were issued in 1999 as a light pick up trucks. Later the upscaled version of Sierra got the name Sierra C3, and was launched in 2001, next year it changed its name to Sierra Denali, and that’s where the history starts.