For 2011, the Chevrolet Silverado is offered in regular, extended and crew cab bodystyles in either Base (Work Truck), LT or LTZ trims, with three cargo bed choices and five wheelbase lengths to select from. Updates for this year include a new Duramax diesel engine rated at 397hp and 765 lb.-ft of torque. Silverado HD now has a max towing capacity (with fifth wheel)of 21,700 lbs. and a conventional towing capacity of 17,000 lbs. Other standard features include trailer sway control, integrated brake control and hill assist, and auto grade breaking help give the driver increased driving confidence with heavy loads. A new "smart" exhaust brake system helps reduce brake pad wear. The Silverado is a sister car to the GMC Sierra.