The refreshed 2024 GMC Sierra Heavy Duty arrives with a new, even more luxurious trim level. At the top of the range, there's now the Denali Ultimate. It's also the latest GMC product to get a rugged AT4X model.

The refreshed Sierra HD receives an updated front end that includes new headlights with bracket-shaped running lamps. Each trim has a unique look for the grille, but this area generally looks bigger and bolder based on the grades on display in the photos. There are six new body colors: Titanium Rush Metallic, Sterling Metallic, Volcanic Red Tintcoat, Redwood Metallic, Meteorite Metallic, and Downpour Metallic.

Gallery: GMC Sierra Heavy Duty Denali Ultimate 2500 And 3500

The updated truck's cabin also receives some tweaks. A newly available 13.4-inch-diagonal infotainment screen dominates the center stack. It supports the wireless versions of Apple CarPlay and Android Auto. Buyers can also get a 12.3-inch-diagonal digital instrument cluster. GMC claims there are "more premium materials" for the interior.

The 2024 Sierra Heavy Duty's powertrain options are the same as the recently introduced Chevrolet Silverado HD. The 6.6-liter Duramax V8 turbodiesel has upgrades to produce 470 horsepower (346 kilowatts) and 975 pound-feet (1,322 Newton-meters). The other choice is a 6.6-liter gasoline-fueled V8 that makes 401 hp (299 kW) and 464 lb-ft (629 Nm). Both engines hook up to an Allison 10-speed automatic gearbox. Rear- and four-wheel-drive configurations are available.

The 2500HD can tow up to 22,500 pounds, which is a 4,000-pound increase, and the 3500HD can haul as much as 36,000 pounds.

GMC makes the updated Sierra HD a more capable towing machine. An updated version of the Transparent Trailer View system now works with gooseneck and fifth-wheel trailers. In addition, the Trailer Side Blind Zone Alert can monitor the areas around the trailer. Integrated scales monitor whether the truck and trailer exceed the gross combined weight rating. The improved adaptive cruise control works while towing by accounting for the additional drag and increased braking distance.

2024 GMC Sierra 2500 HD Denali Ultimate
2024 GMC Sierra 2500 HD Denali Ultimate

You can identify the new Denali Ultimate from its dark Vader chrome exterior trim. It rides on 20-inch wheels that mix a machined finish and high-gloss accents. The truck also comes with a six-way MultiPro Tailgate and power side steps. A unique badge shows the topography of Mount Denali.

Inside, the Denali Ultimate has full-grain leather upholstery in the trim exclusive color Alpine Umber, and there's dark Paldao wood as trim around the cabin. The headliner, visors, and portions of the A- and B-pillars are microsuede.

Amenities in the range-topping truck include 16-way power adjustable and massaging front seats. The stereo is a 12-speaker setup from Bose. Other features include a rear camera mirror, 15-inch head-up display, and a power sunroof.

The refreshed 2024 GMC Sierra HD begins deliveries in the first quarter of 2023. The AT4X joins the range later in 2023. There's no pricing available at this time.

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