Cat C13 6 Cylinder 12.5 L Ultra Low Sulfur Diesel 525 hp Engine, 2004 US EPA Label, Eaton Fuller 10-Speed Manual Transmission, 12000 lb Front Axle, 40000 lb Rears, 52000 lb GVWR, Air Ride Cab, Aluminum Outer Wheels, 11R22.5, Air Trac Air Ride Suspension, 200 in Wheelbase, Air Sliding 5th Wheel, Dual Fuel Tanks