1994 Mack RD688 Tri-Axle Dump Truck. 1994 Mack RD688 Tri-Axle Dump Truck in great condition- White exterior with a Black Dump Bed and a Black interior- Equipped with a 350hp E7 Mack Diesel with an 811 Eaton Fuller Manual transmission- Currently with 112000 original Miles!- 44000 pounds rears- Camelback Suspension- Double Frame- Engine Brake- 18 foot Steel Dump Body- Good Tires all round as well...