This is the cousin of the 2020 Silverado HD that we saw last month. The 2020 GMC Sierra HD comes in SLT, AT4 and Denali trims.
Compared with the outgoing model, the new Sierra HD has a longer wheelbase, a taller, more dominant hood line and taller overall height. A larger grille complements the functional hood scoop to feed cold air to the Duramax turbo diesel. The improvements also include a 1-inch-lower bed lift-in height compared with the 2019 Sierra Heavy Duty, offering easier loading and fifth-wheel and gooseneck trailer hitching.
On the exterior, the new Sierra HD is highlighted by new signature lighting, including prominent “light blades”. LEDs are also used for the headlamps, taillamps, optional fog lamps and other illuminative elements, including the optional roof marker lights—standard on all dual-rear-wheel HDs and all Sierra HD Denalis (except where prohibited by law).
2020 GMC Sierra 2500 HD AT4
Interiors get leather-appointed seating with mini-perforated inserts, dark-tinted and textured aluminum finishes on the steering wheel, center stack and sill plates, and all-weather floor liners.
The AT4 models get off-road suspension, Rancho Shocks, skid plates, Eaton locking rear differential, 18-inch wheels (20-inch optional) wrapped with Michelin all-terrain tires, Traction Select System with specific Off-Road mode, Hill Descent Control & Hill Start Assist, 15-inch diagonal Head-Up Display with Off-Road Inclinometer, and HD Surround Vision1 for low-speed views of vehicle surroundings.
Options list includes 15 camera views including a transparent trailer view, Auto Electric Park Brake to automatically apply the parking brake to help maintain truck position when hitching, larger door-mounted trailering mirrors, Trailer Sway Control, Digital Variable Steering Assist, and six-function MultiPro tailgate.
The 6.6L Duramax turbo diesel engine offers an SAE-certified 445 hp and 1,234 Nm (910 lb-ft) of torque, paired with a new 10-speed Allison automatic transmission. GMC said that the bigger frame, stronger propulsion and smarter technologies are expected to deliver dramatically greater towing capacity than previous models, well in excess of 30,000 pounds (13,608 kg).
The 2020 Sierra HD goes on sale later this year in 2500HD and 3500HD dual rear wheel and single rear wheel configurations.