Machine description: Mack 6 Cylinder Engine, Allison Automatic Transmission, 9072 kg Front Axle, 20866 kg Rears, 29938 kg GVWR, 425/65R22.5 Front Tires, 11R22.5 Rear Tires, Double Frame, Hendrickson Haulmaax Rubber over W... more info about the 2003 Mack MR688S.