Machine description: DM TANDEM MACK WITH 237 MACK ENGINE, 5-SPEED TRANS WITH HIGH AND LOW, 44,000LB REARS, DOUBLE-FRAMED, CAMELBACK SUSPENSION, SPOKE WHEELS, 11R24.5 TIRES, INFRAMED ENGINE AROUND 20,000 MILES AGO, RUNS GO... more info about the 1979 Mack DM685S.