2020 GMC Sierra Duramax diesel first drive: Smooth operator

“The inline six is naturally balanced, so we don’t need the additional rotating inertia of balancing shafts,” he says. “And because we have one cylinder head with a pair of overhead camshafts, the engine is lighter and creates less friction than a V configuration.”
So how does the GM straight-six stack up? Ford’s 3.0-liter turbo-diesel V6 (launched in 2018) packs 250 hp and 444 lb-ft of torque. And Ram’s re-tuned 3.0-liter V6 generates 260 hp and 480 lb-ft of torque. In terms of fuel efficiency, Ram hasn’t announced what that Ecodiesel can deliver. But Ford’s Power Stroke hits 22 mpg city and 30 on the highway in 2WD applications. The Chevy Silverado is the big winner with a 23 mpg city and 33 mpg highway using the same engine as GMC. Oddly, the Sierra’s subdued styling takes a significant fuel economy highway hit. Two-wheel drive Sierras return 23 mpg city and 30 mpg highway. And 4X4s will see those figures drop to 22 mpg city and 26 mpg highway.
The new six comes paired to GM’s 10-speed automatic and 3.23:1 gears in the axles. That allows a maximum towing capacity of 9,100 pounds and a maximum payload of 1,830 pounds. Again, that’s 200 pounds under towing capacity than the Chevy and 40 pounds less payload. The new diesel is available in SLE, Elevation, SLT, AT4 and Denali trims. The cost? It’s priced right on top of the 6.2-liter V8—$2,495. GMC predicts it will make up around ten percent of all Sierra sales.