• Both the GMC 2500HD and 3500HD receive updated styling inside and out for the 2024 model year.
  • V-8 Duramax diesel models gain horsepower and torque while the gas-drinking counterparts add a 10-speed automatic transmission.
  • GMC is adding a Denali Ultimate trim to the top of the heavy-duty lineup and announced an off-roading AT4X will join the ranks later in the model year.

The heavy-duty GMC Sierra 2500HD and 3500HD are getting a refresh for the 2024 model year, complete with a redesigned front end, a fancier interior, and a new transmission. The addition of two trim levels, one for off-road adventures and the other for a cushier work-truck experience, will give HD truck buyers the luxury of more choices.

Increased Capabilities

GMC is adding to the arms race that is heavy-duty truck power figures by making updates to the 2024 Sierra 2500HD and 3500HD. However, power figures for the 6.6-liter V-8 engine don't change for 2024; the thumping V-8 continues to produce 401 horsepower and 464 pound-feet of torque. What does change is that GMC ditched the old six-speed automatic transmission in favor of the 10-speed automatic, which is shared with the diesel; GMC claims the new transmission matches better with the engine’s power curve.

gmc sierra denali ultimate heavy duty pulling a trailerView Photos
GMC

The 6.6-liter Duramax V-8 diesel produces 470 horsepower and gets awfully close to 1000 pound-feet of torque, generating 975 pound-feet. Those figures are up from 445 horsepower and 910 pound-feet on the outgoing model. According to GMC, the extra power (and efficiency) are thanks to numerous uprades to the engine, including a more efficient turbocharger that helps generate 25 percent more low-end torque than the current-generation truck. Max tow ratings for the 2500HD and 3500HD are 22,500 and 36,000 pounds. Opting for the crew-cab variant of the 2500HD sacrifices 600 pounds of towing capability, bringing the max figure to 21,900.

Luxe Accommodations

Heavy-duty work trucks are first and foremost for, well, work. But GMC is known for adding premium touches to help that work along. Whether you are talking about the heavy-duty or half-ton versions, the Sierra has long been a more upscale alternative to its sibling, the Chevy Silverado. The newly added Denali Ultimate rides on exclusive 20-inch machined aluminum wheels with gloss-black accents. Inside, there's open-pore Paldao wood to accompany the full-grain leather seen throughout and niceties including massaging seats and a power sunroof. Cosmetic touches include a unique grille with GMC badging finished in Vader Chrome, plus special fender badging that features topography of Mount Denali. Slightly more unexpected are the redesigned headlights, which play an animation as the driver approaches the vehicle, turns it on, or uses the turn signal.

There are six new paint choices as well as new wheel designs for SLE, AT4, and Denali trims. Inside, the heavy-duty Sierras add a larger optional 13.4-inch center display alongside the newly optional 12.3-inch digital instrument cluster. All but the base Pro trim level's infotainment systems integrate Google apps and wireless Apple CarPlay and Android Auto capability. There's also a new 15-inch multicolor head-up display.

The Sierra HD already had the expected safety aids including forward-collision and lane-departure warning systems, but now adds (optionally) rear cross-traffic braking and trailer-side side blind-spot monitoring. More to the point for a heavy-duty truck with this kind of towing ability, there are several new trailering assist features. Cameras help the driver line up a hitch or fifth wheel, and there's an optional accessory camera for the back of a trailer to give drivers a view behind them. Also new are adaptive cruise control while trailering and an alert to let drivers know if they have exceeded their truck's gross vehicle weight rating.

2024 gmc sierra hd at4xView Photos
2024 Sierra AT4.
GMC

Fancy Some Off-Roading? Fancy Off-Roading

The AT4X is something to look forward to, but this off-road-intended Sierra HD model isn't coming until later in 2024. The rest of the heavy-duty Sierra trucks—Pro, SLE, SLT, AT4 (pictured above), Denali, and Denali Ultimate—are set to begin arriving in dealerships during the first quarter of 2023. GMC doesn't intend to release any pricing until closer to their release dates, but current Sierra 2500HD models start around the $40,000 mark, with Denali trims climbing well past $70,000. We'd expect the Denali Ultimate to climb well above that number.

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Headshot of Jack Fitzgerald
Jack Fitzgerald
Associate News Editor

Jack Fitzgerald’s love for cars stems from his as yet unshakable addiction to Formula 1.
After a brief stint as a detailer for a local dealership group in college, he knew he needed a more permanent way to drive all the new cars he couldn’t afford and decided to pursue a career in auto writing. By hounding his college professors at the University of Wisconsin-Milwaukee, he was able to travel Wisconsin seeking out stories in the auto world before landing his dream job at Car and Driver. His new goal is to delay the inevitable demise of his 2010 Volkswagen Golf.