Chopper In Windrow Or Forward Position Belt. John Deere: Combine: 9400 (s/n 640101 and on), Chopper, Windrow Or Forward Position: John Deere: Combine: 9410, Clean Grain Elevator Countershaft: John Deere: Combine: 6600, 6620, 6622, 7700, 7720, 7721, Clean Grain Elevator: John Deere: Combine: 8820, Straw Chopper, Short Rear: John Deere: Combine: 9450.