The 2025 GMC Sierra AT4 HD is a heavy-duty pickup truck that is designed for off-roading. It is part of the GMC Sierra lineup, which also includes the 1500, 2500HD, and 3500HD models. The AT4 HD is available in both crew cab and double cab configurations, and it comes with a variety of features that are designed to improve its off-road performance, including a lifted suspension, all-terrain tires, and a locking rear differential.
The 2025 GMC Sierra AT4 HD is powered by a 6.6-liter V8 engine that produces 401 horsepower and 464 lb-ft of torque. It is mated to a six-speed automatic transmission and four-wheel drive is standard. The AT4 HD has a maximum towing capacity of 15,400 pounds and a maximum payload capacity of 3,270 pounds.