Machine description: Cat 3406B Diesel 400 hp Engine, Eaton Fuller 9-Speed Manual Transmission, 12000 lb Front Axle, 40000 lb Rears, Aluminum Front Wheels, 11R24.5, Air Ride Suspension, 185 in Wheelbase, Air Sliding 5th Wh... more info about the 1989 Peterbilt 378.