GMC Sierra 4WD AT4 is a trim level of the GMC Sierra full-size pickup truck. It is designed to give the vehicle off-road capability, with a focus on advanced safety and performance technologies. It comes with advanced 4WD technology, a powerful 3.0L turbo-diesel V6 engine, a 10-speed automatic transmission, an off-road suspension, Hill Descent Control and MultiPro Tailgate. It also includes several exclusive styling cues and advanced driver-assistance features.