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2017 Chevy Silverado HD, GMC Sierra HD get new Duramax diesel

The 2017 Chevy Silverado HD and GMC Sierra HD are available with a redesigned 6.6L Duramax turbo-diesel V8 that produces an unprecedented 445 horsepower at 2,800 rpm and―wait for it―910 lb-ft of torque at just 1,600 rpm, General Motors announced.

Along with this 19% increase in max torque, the new Duramax offers quieter and smoother performance for greater refinement. In fact, engine noise at idle is reduced 38%.

Only the bore and stroke dimensions were retained, while a new, GM-developed control system was incorporated.

“Nearly everything about the Duramax is new, designed to produce more torque at lower rpm and more confidence when trailering or hauling,” said Gary Arvan, chief engineer. “You’ll also notice the refinement improvements the moment you start the engine, and appreciate them as you cruise quietly down the highway—with or without a trailer.”

The proven Allison 1000 6-speed automatic transmission teams up with the new 6.6L Duramax. It has been substantially upgraded to accommodate the engine’s higher torque capacity, including a new torque converter.