All-New Duramax 6.6L Diesel Is Our Most Powerful Ever

Greater horsepower, torque supports more confident trailering on 2017 Sierra HD

2017 GMC Sierra Denali 3500HD
2017 GMC Sierra Denali 3500HD

DALLAS — When it comes to horsepower from a diesel engine, the 2017 GMC Sierra HD tops the segment with an SAE-certified 445 hp (332 kW) from an all-new Duramax 6.6L V-8 turbo-diesel. And when it comes to the torque that enables effortless trailering and hauling, it also delivers more than ever: an SAE-certified net 910 lb.-ft. of torque (1,234 Nm) to make easier work of the heaviest loads. 

The 2017 Sierra HD was introduced today in Texas, where more heavy-duty pickups are sold than in any other state, and where Dallas and Houston are two of the largest markets for the top-of-the-line Sierra Denali HD, which accounts for approximately 50 percent of Sierra HD sales nationally.

“GMC Sierra HD trucks and the Duramax diesel have a long-established legacy of offering customers confidence-inspiring capability for the largest tasks,” said Duncan Aldred, vice president of GMC Sales and Marketing. “With the new Duramax and additional enhancements, the 2017 Sierra HD takes the combination of refinement and capability to an unprecedented level.”

Along with a 19 percent increase in max torque over the current Duramax 6.6L and segment-best horsepower, the redesigned turbo-diesel’s performance is quieter and smoother, for greater refinement and more confidence when trailering or hauling.

The new Duramax 6.6L is a next-generation redesign of the venerable turbo-diesel engine and incorporates a new, GM-developed control system. The Duramax’s signature low-rpm torque production hasn’t changed, offering 90 percent of peak torque at a low 1,550 rpm and sustaining it through 2,850 rpm — an attribute that contributes to the Sierra HD’s confident pulling power.

A new, patent-pending vehicle air intake system — distinguished on the Sierra HD by a bold hood scoop — drives cool, dry air into the engine for sustained performance and cooler engine temperatures during difficult conditions such as trailering on steep grades. Cooler air helps the engine run better under load, especially in conditions where engine and transmission temperatures can rise quickly. That allows the Duramax to maintain more power and vehicle speed when trailering in the toughest conditions.

Driveline enhancements were made to increase strength and enhance durability, including a stronger front prop shaft and larger U-joints compared to previous Duramax-equipped Sierra HD models.

Additional highlights include:

  • New full-length, damped steel oil pan that contributes to quietness
  • New rocker cover/fuel system acoustical treatments
  • B20 bio-diesel compatibility
  • SAE-certified 445 net horsepower (332 kW) at 2,800 rpm
  • SAE-certified 910 net lb.-ft. of torque (1,234 Nm) at 1,600 rpm

The new Duramax 6.6L turbo-diesel engine is produced with locally and globally sourced parts at GM’s manufacturing facility in Moraine, Ohio. It will be available in the Sierra HD in early 2017.

2017 Sierra HD lineup

When it comes to delivering the capability on which GMC’s reputation was forged, Sierra 2500HD and 3500HD models — including Sierra Denali HD — are offered with gas and Duramax diesel propulsion systems. They enable a maximum conventional trailering rating of 20,000 pounds (9,072 kg) and a max fifth-wheel/gooseneck trailering rating of 23,300 pounds (10,568 kg).

Regular, double cab and crew cab models are offered across the lineup, with the premium Sierra Denali HD — the ultimate expression of GMC’s Professional Grade ethos — offered exclusively as a crew cab. It matches GMC’s do-it-all capability with distinctive styling elements, premium materials and upscale interior amenities.

Additionally, the All Terrain HD premium off-road package is the most capable off-pavement model, featuring unique exterior details and 18-inch chrome aluminum wheels with all-terrain tires, the Z71 suspension with Rancho twin-tube shocks and more.

In addition to the new Duramax 6.6L turbo-diesel engine, the 2017 Sierra HD lineup offers Teen Driver, which allows parents to set controls, review driving habits and encourage safe driving habits when they are not in the vehicle.

Additional vehicle highlights:

  • An available Gooseneck/5th Wheel Trailering Prep Package makes Sierra HD models ready to tow larger trailers right from the factory.
  • Available Trailering Camera System by EchoMaster® provides multiple views of a trailer and the area around the truck/trailer combo.
  • Digital Steering Assist power steering on select models senses speed to enable ease of handling at low speeds and improved steering feel at highway speeds. It helps make trailering easier when parking or on the road.
  • HID projector-beam headlamps with GMC-signature LED lighting is standard on all models
  • Available wireless phone charging (standard on Denali)
  • Available remote locking tailgate (standard on Denali)

GMC has manufactured trucks since 1902, with innovation and engineering excellence built into all GMC vehicles. The brand is evolving to offer more fuel-efficient trucks and crossovers, including the Terrain small SUV and Acadia crossover. GMC’s highest-volume vehicle, the Sierra pickup, is the most powerful light-duty pickup on the market, and the first full-size pickup to receive the highest-possible five-star Overall Vehicle Score for safety since the National Highway Traffic Safety Administration changed its New Car Assessment Program for the 2011 model year. Details on all GMC models are available at http://www.gmc.com/, on Twitter at @thisisgmc or at http://www.facebook.com/gmc.