2015 GMC Sierra HD Preview

Jeff Youngs | Oct 04, 2013
  • Maximum payload rating is 7,374 lbs.
  • Maximum standard tow rating is 19,600 lbs.
  • Maximum 5th-wheel tow rating is 23,200 lbs.
  • Standard 6.0-liter V-8 engine is CNG-compatible
  • Optional 6.6-liter V-8 turbo-diesel is B20 bio-diesel compatible
  • Standard trailer sway control
  • Standard hill-start assist
  • Standard auto grade braking
  • Available diesel exhaust brake switch


The 2015 GMC Sierra HD is a heavy-duty pickup truck offered in 2500 and 3500 model series, and in Work Truck, SLE, SLT, and Denali trim levels. Three cab styles, two bed lengths, two engine choices, two drivetrain choices, and a variety of axle ratios give truck buyers up to 150 different combinations from which to select, according to GMC.

Exterior Features

For 2015, a new Double Cab model with conventionally hinged doors replaces the previous Extended Cab model with clamshell-style doors. All 2015 Sierra HD models feature an inlaid door design, contributing to greater aerodynamics and improved fuel economy, according to GMC. Rolled-form steel cargo boxes feature two-tier loading and standard corner step bumpers, and the Sierra HD offers upper bed cargo tie-downs, under-rail cargo bed lighting, a spray-in bedliner, and an EZ Lift tailgate. A unique grille, body-color bumpers, and a more upscale appearance separate the luxury-themed Denali trim level from other Sierra HD variants.

Interior Features

Inside, the 2015 Sierra HD Denali is outfitted with premium leather upholstery, heated and ventilated front seats, a heated steering wheel, real aluminum trim, and soft-touch interior surfaces. The Denali also gets an exclusive 8-inch configurable gauge cluster display, and comes standard with a premium audio system. All new 2015 Sierra HD models are equipped with controls that the automaker says can be operated while the driver is wearing work gloves, and most include a GMC IntelliLink touch-screen infotainment system with Bluetooth connectivity.

Optional Features

One option that Sierra HD buyers might wish to add is an Integrated Trailer Brake Controller that includes a Gain display for the instrument panel. A Z71 package is also offered, adding off-road-ready equipment to the truck, and GMC offers numerous comfort, technology, and safety upgrades, depending on the trim level selected.

Under the Hood

The 2015 GMC Sierra HD models come standard with a 6.0-liter V-8 engine generating 360 horsepower at 5,400 rpm and 380 lb.-ft. of torque at 4,200 rpm. The engine is E85-compatible and can operate on Compressed Natural Gas. A 6-speed automatic transmission delivers the power to the rear (2WD) or all four wheels (4WD).

As an option, the Sierra HD is offered with a 6.6-liter turbo-diesel V-8 engine dubbed "Duramax." The turbo-diesel makes 397 horsepower at 3,000 rpm and 765 lb.-ft. of torque at 1,600 rpm, and is paired with an Allison 1000 6-speed automatic transmission and choice between 2WD or 4WD. The Duramax engine is B20 bio-diesel compatible, and a diesel exhaust brake switch is available with this power plant.

Depending on the vehicle combination, a Sierra HD can tow up to 19,600 lbs. using a conventional trailer hitch, and up to 23,200 lbs. using a 5th-wheel hitch. Maximum payload capacity measures 7,374 lbs. GMC includes free scheduled maintenance for the first 2 years or 24,000 miles of ownership.


In addition to 6 standard air bags, the 2015 GMC Sierra HD models can be optioned with a reversing camera, park-assist sensors, lane-departure warning system, and a forward-collision alert system. A Safety Alert Seat vibrates when the latter two features identify a potential threat, in order to get the driver's attention.


GMC IntelliLink is standard for all models except the Sierra HD Work Truck. It includes an 8-inch color touch-screen display, Bluetooth connectivity, Pandora Internet radio connection, 5 USB ports, SD card slot, and more. It can be upgraded with a premium audio system and a navigation system.
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