Under the hood, the 2026 GMC Sierra 2500 HD offers two impressive engine configurations to match your specific hauling needs: 6.6L V8 Gas Engine: This standard engine delivers 401 horsepower at 5,200 rpm and 464 lb-ft of torque at 4,000 rpm. 6.6L Duramax Turbo-Diesel V8 Engine: For those who require maximum torque, this available heavy-duty diesel engine generates 470 horsepower at 2,800 rpm and an immense 975 lb-ft of torque at 1,600 rpm. Both engines pair seamlessly with the proven Allison® 10-speed automatic transmission. This advanced transmission includes a Tow/Haul mode to reduce shift cycling for better control and cooling when moving heavy loads. It also features Auto Grade Braking, which automatically downshifts to enable engine braking on downhill grades, helping slow the truck and reduce brake wear.

We know Riverton drivers use their trucks for serious towing. The 2026 Sierra 2500 HD delivers a maximum available tow rating of up to 22,390 lbs when properly equipped. Hooking up your trailer is simpler than ever with standard Hitch Guidance. You can also configure your truck with the available GMC MultiPro Tailgate, which offers six distinct functions to improve loading, unloading, and accessing the cargo box. From standard beds to long beds, and Regular, Double, or Crew Cab configurations, you can spec this truck to fit your exact payload requirements.

If your plans involve leaving the pavement behind, the available AT4 and AT4X trims offer serious off-road upgrades. The highly capable AT4X model features advanced DSSV dampers, a rear electronic-locking differential, and aggressive 35-inch Goodyear Territory MT tires. With a larger steel transfer case skid plate and a front aluminum skid plate, the AT4X is built to conquer the backcountry.

he 2026 GMC Sierra 2500 HD keeps you connected no matter how far you travel from Fremont County. The available 13.4-inch diagonal GMC Premium Infotainment System with Google built-in provides intuitive navigation, entertainment, and hands-free voice control. Depending on the trim level, the interior ranges from rugged and practical to incredibly luxurious. The Denali Ultimate trim elevates your daily drive with 16-way heated and ventilated power front seats featuring a massage function. It also surrounds you with premium materials like full-grain leather seating and authentic Vanta ash wood trim.

Driving a heavy-duty truck requires total awareness. The Sierra 2500 HD comes standard with Sierra HD Pro Safety, a suite of advanced driver-assistance features that look out for you on every trip. Whether you are navigating downtown Riverton or cruising down Highway 26, these integrated safety systems give you total peace of mind. Stop by Fremont GMC in Riverton, WY, to talk with our team of experts. We will help you explore the features, find the perfect trim level, and take the 2026 GMC Sierra 2500 HD for a test drive today.