The 2026 GMC Sierra 2500HD AT4 is an exceptional heavy-duty pickup built to conquer any challenge. Equipped with the powerful Duramax 6.6L V8 Turbodiesel engine, this Sierra AT4 delivers an impressive 470 horsepower and 975 lb-ft of torque for unparalleled capability. - 6.6L V8 Diesel Turbocharged (Duramax) (B20-Diesel Compatible) (Includes (K05) Engine Block Heater) (470 hp [350.5 kW] @ 2800 rpm, 975 lb-ft of torque [1322 Nm] @ 1600 rpm) - 7 Speakers - Bose Premium 7-Speaker Sound System - Premium audio system: Premium GMC Infotainment System - SiriusXM with 360L Trial Subscription - Heated / Cooled Leather Seats - Local Trade - Non-Smoker - One Owner - Clean Carfax - Off-Road Suspension - 2-Speed Active Transfer Case - Spray-on Pickup Bedliner with GMC Logo - Trailer Cam Provisions and Trailer Viewing Software - Wireless Charging - Wireless Phone Projection This Sierra AT4 is built to take on any terrain with confidence. The advanced off-road suspension, 2-speed transfer case, and premium features like the Bose audio system and wireless charging ensure you'll enjoy every mile, whether hauling the heaviest loads or exploring the great outdoors. With its striking black exterior, premium interior, and uncompromising capability, this 2026 GMC Sierra 2500HD AT4 is the ultimate heavy-duty workhorse. Why buy from Greg Lair GMC? It's a great question with an even better answer! We've been a local fixture in the Panhandle for nearly 40 years, putting customers from Amarillo and the Panhandle first every single day. We set ourselves apart as the home of the FREE Lifetime Powertrain Warranty on all inventory under 100,000 miles. From our hassle-free buying process to our thorough multi-point inspections by Certified GM Technicians, we make sure your next vehicle is safe, reliable, and ready for the road. Stop by today and see the Greg Lair difference for yourself!.