Machine description: Mack 6 Cylinder 672 cid Diesel 350 hp Engine, 1989 US EPA Label, 2383 Engine hrs, Engine Brake, Eaton Fuller 15-Speed Manual Transmission, 11R22.5 Front Tires, 11R24.5 Rear Tires, Spring over Walking ... more info about the 1989 Mack RD688S.