GMC introduced the AT4X as the flagship off-road entry in the 4th-generation Sierra lineup, blending extreme factory trail performance with executive-level interior luxury. It commands instant road presence with dark-nickel exterior accents, red recovery hooks, a raised factory suspension lift, and aggressive 33-inch Goodyear Wrangler Territory MT tires. Rather than forcing buyers to choose between harsh off-road tuning and daily comfort, it pairs full-grain leather massaging seats and a 12-speaker Bose sound system with serious high-speed terrain hardware.

Under the hood sits a naturally aspirated 6.2-liter EcoTec3 V8 producing 420 horsepower and 460 lb-ft of torque (or an available 3.0L Duramax turbo-diesel with 495 lb-ft of torque), mated to a fast-shifting 10-speed automatic transmission. The chassis features Multimatic DSSV spool-valve dampers that continuously adjust fluid flow for precise body control over washouts and rock crawls. Equipped with front and rear e-locking differentials, a specialized Terrain Mode with one-pedal rock crawling, and heavy-duty steel transfer case skid plates, it provides exceptional traction across technical landscapes.