Meet the 2026 GMC Sierra 2500HD AT4, a heavy-duty truck purpose-built for those who demand capability without compromise. This Black pickup represents serious workmanship and refined interior comfort, delivering the power and features you need whether you're managing a job site, towing a trailer, or tackling challenging terrain.- Duramax 6.6L V8 Turbodiesel engine with 10-speed automatic and 4WD capability- AT4 Preferred Package with off-road suspension and 2-speed active transfer case- Gooseneck/5th wheel prep package for serious towing applications- X31 Off-Road Package featuring hill descent control and terrain control systems- Bose premium 7-speaker sound system with SiriusXM 360L trial subscription- HD surround vision with bed view camera and trailer camera provisions- Wireless phone projection and charging for seamless device integration- Heated and ventilated leather front seats with heated rear seating- Ultrasonic front and rear park assist with rear cross traffic alert- 20-inch high gloss black aluminum wheels on a spray-on bedliner with GMC logo- Remote vehicle starter system and keyless open and start functionality- Power sunroof with power sliding rear window and defogger- 120-volt power outlets in bed and instrument panel for jobsite convenience- Fresh oil change completed, ready for immediate useThe Sierra 2500HD AT4 combines work-ready engineering with daily-driver refinement. Its diesel engine delivers the torque and towing capacity you expect from the Duramax platform, while the four-wheel-drive system with electronic locking front differential handles rough terrain and challenging conditions. The active transfer case provides on-demand power distribution, ensuring traction when you need it most.Inside the cab, you'll find premium appointments designed for long hours of comfortable driving. The leather-appointed front seats offer heating and ventilation, adjustable lumbar support, and memory functions for the driver. Dual-zone automatic climate control maintains your preferred temperature, while the heated steering wheel keeps your hands comfortable in cold weather. The overhead console with integrated safety features keeps important controls within reach.Technology integration sets this truck apart. The premium GMC infotainment system works seamlessly with your smartphone through wireless projection, eliminating the need for cables. The Bose audio system delivers clear sound quality throughout the cab, enhanced by SiriusXM's 360L trial subscription. Multiple USB ports and wireless charging keep your devices powered, while the steering wheel controls let you manage entertainment without taking your hands away during drives.Safety features provide confidence in all driving conditions. Automatic emergency braking, forward collision alert, front pedestrian braking, and lane departure warning help prevent accidents. The ultrasonic park assist system makes parking easier, while the rear cross traffic alert and trailer side blind zone alert provide awareness in challenging situations. OnStar emergency response services connect you to help when needed.The AT4 trim distinguishes itself with genuine off-road capability. The X31 Off-Road Package includes terrain control for managing different surfaces, while the off-road suspension articulation handles rough ground. Hill descent control assists on steep declines, and the spray-on bedliner protects your investment whether you're hauling materials or equipment. This truck works as hard as you do, backed by thoughtful engineering and premium finishing touches that make ownership rewarding every single day.