Meet the 2023 GMC Sierra 1500 AT4 a Super Certified diesel workhorse dressed in black and ready for whatever you throw at it. The Duramax 3.0L turbo-diesel I6 delivers an impressive 305 hp and 495 lb-ft of torque paired to a smooth 10-speed automatic and a rugged 4WD system, so towing, hauling and highway passing feel confident and controlled. Off-road friendly AT4 touches include tow hooks, locking/limited-slip differential, integrated tailgate step and a bed liner that protect cargo and make everyday jobs easier.