GMC Sierra HD (2020)

The ProGrade Trailering System also includes an in-vehicle Trailering App with Trailer Light Test, Trailer Electrical Diagnostics, Trailer Tire Pressure and Temperature Monitoring, Pre- Maintenance Reminders and Departure Checklist. Many of the Trailering app's functions, including the lighting test and pre-departure checklist, are also available with the myGMC mobile app, a feature that offers great convenience when outside the truck or trailer.

Additional available technologies and hardware to aid trailering include:

• Auto Electric Park Brake to automatically apply the parking brake to help maintain truck position when hitching.
• All-new Park Grade Hold Assist enhances hill hold by using braking effort at each wheel for an extended period of time.
• All-new larger, door-mounted trailering mirrors with a four-bar link providing power extend and retract for the driver and passenger sides.
• Integrated trailer brake controller that works with the trailer profile in the Trailering App to recall a specified trailer's most recent gain setting.
• Tow/Haul mode that remains engaged on the next key-on cycle, for up to four hours; includes a reminder the feature is engaged.
• Hill Start Assist and Hill Descent Control.
• Trailer Sway Control.
• Auto Grade Braking and Diesel Exhaust Braking.
• Digital Variable Steering Assist that dynamically optimizes power steering according to driving scenarios, including trailering, and enables features like road pull compensation.
• Trailering Info Label placed on the driver's door jamb that clearly calls out the truck's specific trailering information, including curb weight, GVWR, GCWR, maximum payload, maximum tongue weight and rear GAWR.

Bigger and bolder

The 2020 GMC Sierra HD has a commanding, powerful design rooted in a new architecture with larger proportions. It is taller and longer, with a more confident stance defined by a bold design that epitomizes GMC's signature refinement and technologically driven attention to detail.

"We took every opportunity to visually express the strength and capability that lies beneath the surface," says Matt Noone, director of GMC exterior design. "The elevated hood line, the strong shoulders, the striking front grille - these cues communicate the strength and performance that have been engineered and built into each and every Sierra Heavy Duty."

The all-new Sierra HD is highlighted by new signature lighting, including prominent "light blades" that deliver LED illumination for the daytime running lamps. LEDs are also used for the headlamps, taillamps, available fog lamps and other illuminative elements, including the available roof marker lights standard on all dual-rear-wheel HDs and all Sierra HD Denalis except where prohibited by law.

Inside, the Sierra HD's new interior has best-in-class front head- and legroom (maximum), with Crew Cab models. A higher seating position complements the truck's taller profile to offer a confident view from behind the wheel. Additional optimized ergonomics emphasize easy, intuitive interaction with the vehicle's available technologies, such as a heavy-duty segment-first head-up display and GMC's latest touchscreen infotainment systems.

Denali-exclusive materials - including premium leather-appointed seating, authentic open-pore wood trim and dark-finish aluminum decor - raise the interior's refinement. The leather appointments have a distinctive, large-pebbled grain with a contrasting stitch pattern that is premium in appearance and touch without sacrificing durability, and the wood trim features an open-pore texture evocative of hand-planed furniture.

Compared to the current model, the new Sierra Heavy Duty has:

• A longer wheelbase, a taller, more dominant hood line and taller overall height.
• A larger grille and complementing functional hood scoop to feed an advanced cooling system for the Duramax turbo diesel.
• Class-leading heavy-duty cargo bed volume and 12 corner tie-downs with a new, available 120-volt power outlet.
• One-inch-lower bed lift-in height compared to the 2019 Sierra Heavy Duty, providing easier loading and fifth-wheel and gooseneck trailer hitching.
• New, segment-exclusive cargo bed side steps on all box styles, located in front of the rear wheel openings, that complement integrated CornerSteps in the rear bumper to improve access to the cargo area.
• World's first six-function MultiPro tailgate available on all trim levels and standard on SLT, AT4 and Denali.

All-new Sierra AT4 HD: Refined HD Capability Off-Road

The all-new 2020 Sierra Heavy Duty AT4 continues the AT4 brand's growth with a distinctive off-road identity to complement its robust HD capability. Driven by dark chrome exterior finishes and contemporary detailing, Sierra HD AT4 features front and rear bumpers and a grille surround finished in body color. The bold grille design, with its rugged texture, is finished in black chrome and set off by the AT4's distinctive red vertical recovery hooks.

The athletic interior also carries AT4-specific darkened trim, including dark-tinted and textured aluminum finishes on the steering wheel, center stack and sill plates, as well as a unique Jet Black interior with Kalahari color accents in the seats and live stitching. Leather-appointed seating, with mini-perforated inserts and embroidered AT4 badging on the headrests, along with all-weather floor liners, is standard delivering durability with uncompromising comfort.

The new Sierra AT4 Heavy Duty's off-road capabilities are rooted in a unique suspension and supporting technologies that include:

• Off-road suspension, Rancho Shocks, skid plates, Eaton locking rear differential.
• Eighteen-inch wheels wrapped with Michelin all-terrain tires, with 20-inch wheels available.
• Traction Select System with specific Off-Road mode.
• Hill Descent Control and Hill Start Assist.
• Segment-exclusive 15-inch diagonal Head-Up Display with Off-Road Inclinometer.
• HD Surround Vision1 for low-speed views of vehicle surroundings.

Confident trailering power

GMC's legendary Duramax turbo diesel and Allison Transmission pairing continues to offer the ultimate in towing confidence.

The proven Duramax 6.6L turbo-diesel engine offers high torque, high power, low noise and exceptional durability. For the 2020 Sierra HD, the Duramax offers an SAE-certified 445 horsepower and 910 lb-ft of torque. This already powerful engine performs more efficiently thanks to increased cooling capacity delivered in part by improved air induction. A dual-path intake system draws dense, cool air through both the prominent hood scoop and the larger front grille.

The new Sierra HD marks the introduction of an all-new 10-speed Allison automatic transmission - the first-ever offered in the heavy-duty pickup segment. The all-new 10-speed transmission with closer gear spacing allows the engine to operate in an optimal range at all times with varying load and terrain conditions.

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.