I have a FS-609 finisher attached to a C353. I am getting intermittent J72-25 jams when folding. It will make a grinding noise not staple properly and not fold correctly. Have tried replacing some parts that were the same from a FS-601 finisher. When I pull the folding unit out and run by hand everything turns smoothly. No broken gears. I swapped out a clutch, a one-way gear, the knife, a sensor and a belt but still have this issue. just wondering if anybody has had an issue with this finisher when folding. Thanks.