Horsepower 2025 At4 Gmc 6.6 Lt. View detailed specs, features and options for the 2025 gmc sierra 2500hd 4wd crew cab 172 at4 at u.s. A discussion thread on the pros and cons of choosing a 2025 chevy or gmc truck with a gas or a diesel engine.
See how the gmc sierra hd and chevy silverado hd differ in design, performance, technology, and towing capacity. Choose from either a gmc sierra 2500 hd or 3500 hd at4, and learn more about the vehicle specs, trims, and features available.