The 2025 GMC Sierra HD is engineered for those who demand strength, performance, and reliability in their truck. Whether you’re hauling heavy loads, tackling rough terrains, or taking on the toughest jobs, this powerhouse is built to handle it all with unmatched durability and capability.
Powerful 6.6L Engines
Whether you need to haul construction materials or tow livestock trailers, the 2025 Sierra HD outputs plenty of power for the heaviest jobs. It comes standard with a 6.6L V8 gas engine with 401 horsepower and 464 lb-ft of torque. An available 6.6L V8 turbo-diesel engine provides more power and torque, boosting the towing capacity and the off-roading prowess.
Heavy-Duty-Tuned Transmission
Both engines pair with a heavy-duty-tuned Allison 10-speed automatic transmission with electronically controlled overdrive and auto-grade braking. The overdrive feature ensures smooth shifting performance in challenging driving conditions, while the auto-grade braking optimizes the downshifts for easier stopping when driving downhill with a trailer attached. A standard Tow/Haul mode also improves the performance when towing or hauling heavy loads.
Impressive Payload Capacity
The standard gas engine optimizes this heavy-duty truck for hauling, providing a payload capacity of 3,907 lbs on the Sierra 2500 HD Pro trim and 4,696 lbs on the Sierra 3500 HD Pro model.
Massive Towing Power
Maximum towing capacity comes from the turbo-diesel engine, which allows you to pull up to 36,000 lbs, depending on the truck’s model and trim level. Both the Sierra 2500 HD and the Sierra 3500 HD support conventional and 5th-wheel/gooseneck towing, so you can pull a variety of cargo or livestock trailers, as well as RVs.
Tough Off-Roading Features
GMC offers this truck in standard rear-wheel drive, a layout that provides exceptional hauling performance and great fuel economy. Four-wheel drive is available across the lineup, so optimizing this truck for off-road driving is easy. The 4WD configuration comes with an electronic-shift two-speed transfer case that allows you to adjust the power output for various driving conditions, from dry asphalt to mud and deep snow or sand.
The available 31X off-road package optimizes the truck for rugged terrains with twin-tube Rancho shocks and skid plates. Select trims also come equipped with heavy-duty off-roading features, such as Multimatic DSSV dampers, 35-inch mud-terrain tires, and a factory-installed lift for added ground clearance.
Trailering Provisions
To make towing easy, each trim level comes standard with the Trailering Package, which includes a hitch and a hitch platform, four-pin and seven-pin connectors, a 2.5-inch receiver hitch, and a seven-wire electrical harness. Hitch guidance is also standard, allowing for easier alignment.
Ready to learn more about this heavy-duty truck and its tough features? Visit us at Everett Buick GMC in Bryant, AR. We will be here to answer any questions you might have and schedule your test drive.
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