When the trailer is hooked up, the road stretches ahead, and there's a mountain pass between you and the job, this is the truck you want in your driveway. The 2026 GMC Sierra 3500HD AT4 is built to handle serious work without giving up comfort, combining the legendary Duramax® 6.6L V8 Turbo-Diesel and 10-speed automatic transmission with the off-road capability and premium features that make every kilometre more enjoyable.Finished in striking Sterling Metallic with a Jet Black and Kalahari leather interior, this AT4 looks just as impressive pulling into a worksite as it does parked at the lake for the weekend. The AT4 off-road suspension, locking rear differential, skid plates, BFGoodrich® KO3 off-road tires, and Gooseneck/5th Wheel Prep Package give you the confidence to take on demanding jobs and challenging terrain. Whether you're towing heavy equipment, hauling the toys, or heading deep into the backcountry, this Sierra HD is ready for it.Inside, GMC has turned this heavy-duty truck into a first-class command centre. Settle into heated and ventilated leather seats, enjoy the open-air feel of the Power Sunroof, and keep important information in your line of sight with the 15-inch Head-Up Display (HUD). The 13.4-inch GMC Infotainment System with Google Built-In, Bose® Premium Audio System, Rear Camera Mirror, and HD Surround Vision help make long highway drives and busy towing days feel effortless. Add in Adaptive Cruise Control, Trailer Side Blind Zone Alert, and the versatile MultiPro™ Tailgate, and you've got a truck that's as smart as it is capable.From job sites around Trail to weekends exploring the Kootenays, this Sierra 3500HD AT4 is ready for whatever comes next. Visit us in Trail to experience it in person.Key Features:? Duramax® 6.6L Turbo-Diesel V8 & 10-Speed Automatic? AT4 Premium Plus Package with Power Sunroof & Head-Up Display? Bose® Premium Audio & 13.4" GMC Infotainment System? Gooseneck/5th Wheel Prep Package & Advanced Trailering Technology? Heated & Ventilated Leather Seating with Heated Rear Seats