Machine description: Mack 6 Cylinder 11 L Diesel Engine, 6851 Engine hrs, Manual Transmission, 11R22.5, Camelback Spring Suspension, 188 in Wheelbase, PTO, Hydraulic System, 1975 BESELER 70 2700 gal Steel Tank, Tank Linin... more info about the 1989 Mack R688ST.