GMC Sierra 3500HD

Looking like the tough older brother to the Sierra 1500, the heavy-duty trucks feature a fresh front bumper, grille, and lighting, granting them an updated appearance. The lights now feature animation when the driver approaches or uses the turn signals. New trim elements further sharpen the looks.There are six new exterior colors, but they carry an added cost. And the Denali Ultimate has a six-way tailgate with an integrated Kicker audio system.

The cabin looks evolutionary. The shapes and details of the dashboard and other surfaces are a bit different from the Chevrolet truck interiors, but the overall configuration and layout are similar. Some controls, such as the volume and trailer brakes, are in different places and the air vents are oriented differently. In the higher trims, the GMC looks decidedly upscale. The showoff element is an available 12.3-inch instrument panel screen and 13.4-inch infoent tainmscreen. There is a large 15-inch head-up display offered, as well.

As shoppers step through the trims, a long list of conveniences are piled on. The appropriately named Ultimate trim brings so much leather that it is applied to the doors, offset by a microsuede headliner. It has a 12-speaker Bose stereo, 16-way power-adjustable seats with a massage feature, power moonroof, and dark wood trim around the cabin.

The standard engine will remain a 401-hp, 6.6-liter gasoline V8 with 464 lb.-ft. of torque. The 10-speed automatic transmission will allow the engine to better optimize power, compared with the previous six-speed. It’s also likely to improve the big truck’s fuel mileage.

For serious towing chores, there is an optional Duramax 6.6-liter turbodiesel V8 mated to an Allison 10-speed automatic transmission. For 2024, this burly powerplant sees an increase to 470 hp along with a prodigious 975 lb.-ft. of torque. That torque figure is an important number when it comes to heavy-duty pickups because low-end power is a big aid when climbing up steep grades with a trailer in tow.

To that end, the Max Tow package enables the 2500 to have a towing capacity of up to 22,500 pounds in conjunction with the turbodiesel engine—an increase from up to 18,500 pounds with the outgoing version. The Sierra 3500HD with the turbodiesel and a dual rear-wheel setup can tow up to a whopping 36,000 pounds, which is the same as before.

Aiding with towing duties is a raft of clever technologies available to assist with hitching and trailering. This includes bed- and hitch-view cameras, a blind spot warning that factors in the trailer, and a warning if the truck and trailer weight exceeds the vehicle’s gross combined weight rating (GCWR). Plus, there’s a new Adaptive Cruise Control with Trailer feature that factors the additional drag of a trailer when accelerating and the increased braking distances due to the trailer’s extra weight.

The Sierra HD trucks come with forward collision warning, automatic emergency braking with pedestrian detection, lane departure warning, and automatic high beams. Available features include adaptive cruise control, rear cross traffic warning with reverse automatic emergency braking, and trailer-compatible blind spot warning.

GM’s Super Cruise active driving assistance system, which is available on the Sierra 1500, was not added to the HD models.