The 2011 GMC
Sierra 2500 HD is the truck for those seeking a heavy capacity truck, without the need to move large loads and suffer changes to ride dynamics. The standard engine is a 6.0-liter V8 with 360 horsepower. The diesel is a 6.6-liter V8 Duramax with 365 horsepower. The gas variant comes only with a six-speed automatic, while the diesel is hitched exclusively to an Allison 1000 six-speed.