For any of you that have a 9670 combine. Check the rear chopper drive belt tensioner. If the gauge is green, loosen nut until the washer is 1 1/4 inches above the top of the gauge. If the gauge is painted black you should be ok. We had a chopper rotor break this weekend. Had to drive 4 hours to Minn. to find one at a dealer. Too much tension on the belt, broke the drive side shaft off of the rotor. This is for the 9670STS only.