GM just pulled the sheets on the refreshed 2024 GMC Sierra HD, revealing a long list of updates and changes for the heavy-duty pickup truck. Notably, the latest 2024-model-year refresh includes the announcement of the new GMC Sierra HD AT4X, an even-more-capable off-roader trim level set to launch later in the 2023 calendar year following the arrival of the first 2024 GMC Sierra HD units in dealers in Q1 of 2023.
Although GM has yet to release full specs and info on the new 2024 GMC Sierra HD AT4X, The General has disclosed that it will be “seriously off-road capable.” It remains to be seen exactly what will provide said capability, but at this point, we can assume upgrades like a raised ride height, front and rear e-lockers, and knobby Goodyear Territory MT tires. However, per previous GM Authority coverage, it’s now looking as though the new GMC Sierra HD AT4X will not be equipped with Multimatic DSSV dampers, as can found underneath the light-duty Sierra 1500 AT4X.
In terms of exterior styling, we expect the GMC Sierra HD AT4X to be equipped with dark trim and red tow hooks, as well as an abundance of AT4X badges for the front grille, front doors, and rear tailgate. A new bumper treatment up front and in back is also likely.
Under the hood, the 2024 GMC Sierra HD is offered with two engine options, starting with the naturally aspirated 6.6L V8 L8T gasoline engine as standard. Output from the 6.6L V8 L8T is once again rated at 401 horsepower and 464 pound-feet of torque, however, the gasoline engine now connects to the Allison-branded 10-speed automatic transmission, rather than the the GM six-speed automatic transmission equipped by gasoline-powered Sierra HD models prior.
Options include the 6.6L V8 L5P turbodiesel Duramax engine, which is now rated at 470 horsepower and 975 pound-feet of torque, an increase compared to the 445 horsepower and 910 pound-feet of torque produced prior to the 2024-model-year refresh.