A friend is looking at JD 456 round baler. I looked at it. It seems be in great shape, and well taken care of. It seems to be a good deal compared to the asking prices and condition of the ones I see online. I did a search and it seems like folks on here like them. My question - is there any common problems with them he should look into if he buys it? Stuff that may not be common problems for all balers?