The 2021 GMC Sierra Heavy Duty pickup hog mollies are back this year—how could you miss them? Mechanically related to the Chevrolet Silverado HD twins, the GMC versions are comparatively a little more rock ‘n’ roll. New this year are versions of the pickup that take it further off-road (X31) and take it further into superlative naming schemes (Denali Black Diamond). It’s still offered in 2500 and 3500 versions, with single- or dual-rear-wheel configurations, with one of two V-8 engines. Regular-, double-, and crew-cab configurations are available, the last of which is more popular with retail shoppers.
It’s a 7.0 on our rating scale with two important asterisks—heavy-duty pickups aren’t rated for fuel economy or safety. If scored, it would almost certainly sink that number; the truck lacks standard active safety features found on many other new cars and its fuel-economy figures are roughly “LOL.” (Read more about how we rate cars.)
The GMC Sierra HD unabashedly punches a huge hole in the wind. After last year’s update, the heavy-duty pickup added girth and grandeur, most notably in its huge, upright grille that can be lacquered with acres of chrome.
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The body sides are equally impressive for their length and mass. GMC does little to hide the truck’s mass—it’s fine.
A 6.6-liter gas V-8 is standard and makes 401 horsepower. It’s paired to a 6-speed automatic transmission and can lug more than three tons in the bed if needed. A 6.6-liter turbodiesel is a pricey upgrade but comes with eye-popping stats: 445 hp, 910 lb-ft, up to 35,500 pounds of towing. It’s teamed to a smooth 10-speed automatic and better for it.
Crew cabs are more common and are very comfortable places to be for up to five adults. GMC offers short- or long-bed setups (except regular-cab pickups, which only offer a long bed) and its deep and wide bed holds plenty. A trick tailgate is fitted on most trucks and it’s helpful—provided you don’t bang it into a trailer hitch.
Like last year, the Sierra HD is offered in base, SLE, SLT, AT4, and Denali trim levels that start at about $42,000 and run past $80,000. Like other heavy-duty competitors, no two GMC Sierra HDs need to be the same, although most shoppers have considered the crème de la crème: Sierra HD Denali with the optional turbodiesel engine. They’re nice places to be, and they’re also bigger than some apartments.