I'm having trouble with the snapper roll, gathering chain slip clutch, on the left side, wanting to slip in heavy or wet stalk conditions. Last year was my first year with a JD combine and head so I was wondering where I start to fix this, what to look for, if this is a reoccurring problem. Is it easy to get out? I did notice last fall the jaws were covered with oil. Must be from the drive chains on the end of header under the cover. I run around 300 acres a year corn with it. I'll be fixing soon. I can't put up with that this year. Thanks