Receiving a substantial amount of changes for 2011, the 2012 GMC Sierra 3500HD maintains an equally powerful presence this year. Presenting a wide range of configurations that includes single or dual rear wheel versions, Regular, Extended and Crew Cab models of the 2012 Sierra 3500HD seats between 2 to 6 passengers. Beyond physical characteristics, the 2012 GMC Sierra 3500HD trim level range features Work Truck, SLE, SLT and Denali models of the full-sized pickup truck. Purposefully spartan, the Work Truck model includes air conditioning, tilt steering column and dual 12-volt power outlets. OnStar with Turn-by-Turn Navigation, XM satellite radio as well as power windows and door locks are added to the SLE or SLT versions of the 2012 GMC Sierra 3500HD. Heavy-duty work vehicle capacity still present, the 2012 Sierra 3500HD Denali edition adds special premium details. Leather 12-way power front seating, Bose audio system, adjustable drive pedals and a unique-looking grille is found with the Denali trim. Utilizing a 6-speed automatic transmission, two engines are available on the 2012 GMC Sierra 3500HD. Standard power for the one-ton pickup truck is delivered by a 6-liter V-8 engine producing 360 horsepower. For 765 pound-feet of torque, the optional Duramax 6.6 liter turbo-diesel V-8 allows up to 21,700 pounds of towing capacity.