In Reply to: JD 643 slip clutch 6 row posted by KGM on August 20, 2004 at 12:00:15:

KGM,
I think I know what you mean here. There is a slip clutch for every row located 'under' the header to the back, where the shaft runs from row to row. Its not a very big real hard job to change, depending if your shafts cooperate. Depends which row as to how far you have to move things. To start with take the tin sheild off in that row at least and go from there. There is either 2 or 4 little bolts that hold this shield which keeps weeds and stalks from wrapping the rotating shaft. It is the shield that you grease the gearboxes thru. I do hope you take out the top caps and grease EACH row unit, EVERY year from the bottom, until grease comes out the top. Their is a special corn head grease for this. If any seals are leaking very badly its a sign of impending trouble and individual row gear boxes are expensive to fix or replace. Talk to your local JD shop boss.
But with the clutch, you pull the shaft from the end enough to get the clutch unit to drop out the bottom. So not neccessary to pull 'shaft'completely out which loses centers in other rows. Good luck and come back with anything you need. My mind is foggy since its been a long time since doing. In off time not bad job. During rush season time takes twice too long. Is your head the oil bath(new style) on the ends or old style dry roller chain? I have dry old style so your mileage may vary if oil bath.(For the end part). Good luck, have fun!!!