Cummins ISC 6 Cylinder 8.3 L Diesel 315 hp Engine, 2006 US EPA Label, Exhaust Brake, Eaton Fuller FRO11210C 10-Speed Manual Transmission, Double Differential Locks, 16000 lb Front Axle, 40000 lb Rears, Spicer RDP41 Drive Axles, 4.63:1 Axle Ratio, 56000 lb GVWR, Aluminum Wheels, 315/80R22.5 Front Tires, 295/75R22.5 Rear Tires, Double Frame, Air Trac Air Ride Suspension, 235 in Wheelbase, 140 in Cab to Axle, 256 in Cab to End of Frame