The Sierra HD pickup truck has a standard gas-powered 6.6-liter V-8 engine that generates 401 horsepower and 464 pound-feet of torque. It's coupled with a 10-speed automatic transmission and can be driven on rear- or four-wheel drive. Alternatively, you can opt for the Duramax diesel 6.6-liter V-8 engine, which produces 470 horsepower and 975 pound-feet of torque. This engine works with an Allison-certified 10-speed automatic transmission.

For 3500 HD models, you can choose either a single- or dual-rear-wheel axle, which is commonly known as a "dually." The Duramax engine is a great choice for those who regularly tow heavy loads. The Sierra's engine is refined, and the transmission is very responsive. Despite the vague steering at highway speeds, the Sierra HD is more agile than other heavy-duty competitors. The AT4 and AT4X models are designed for off-road suspension and have a locking rear differential. The AT4X AEV has stronger bumpers that can hold a front winch. The Sierra 3500HD can tow as much as 36,000 pounds. It is a truly powerful truck.

The 2024 GMC Sierra 3500 HD has a striking appearance and feel. Its standard and long cargo boxes have built-in steps on both sides of the bed, and the rear bumper has them at each corner. The box can be further customized with LED lighting, movable tie-downs, and a 120-volt outlet. The heavy-duty Sierra's most impressive feature is its innovative multi-function tailgate, which has six different positions, including a work surface and bench. It's a tailgater's paradise.

Looking inside, the dashboard of 2024 GMC Sierra 3500 HD is spacious and easy to navigate with user-friendly switchgear. Most models come with a split-folding front bench that can be substituted for a pair of bucket seats and a complete center console if that’s what you prefer. You can further customize the interior of the Sierra with features like a heads-up display, a heated steering wheel, heated-and-cooled front seats, and wireless charging. For supreme luxury, the newly introduced Denali Ultimate trim is the epitome of elegance. This trim level includes leather-wrapped interior pieces, Paldao wood trim pieces, a soft microsuede headliner, and more.

Each Sierra HD trim level comes with a standard 7-inch touchscreen infotainment system that is compatible with both Apple CarPlay and Android Auto. The 2024 GMC Sierra 3500 HD also has an available 120-volt outlet and mobile hotspot. You have the option for larger touchscreens, which can be further upgraded to include built-in navigation, a Bose audio system, SiriusXM satellite radio, and a rear-seat entertainment system. The Denali and Denali Ultimate trims come standard with a massive 13.4-inch infotainment touchscreen that offers the most integrated experience with technology features like Google Built-in and split-screen navigation. Additionally, GMC offers a smartphone app that can remotely control functions for the Sierra 3500 HD trailer, and the infotainment system allows users to save different trailer profiles to monitor its maintenance.

Regarding safety, the GMC Sierra 3500 HD has a comprehensive camera system with up to 15 different viewing modes, including a "transparent" mode that allows you to virtually see through an attached trailer as if it wasn't there. Additional safety features that come standard include forward-collision warning, automated emergency braking, and lane-departure warning, with available blind-spot monitoring and rear cross-traffic alert.