I've got a little 7700 that we plant with and when I first bought it (well used), the rockshaft had a tremendous amount of slack between the steel shaft and the cast housing. I was a little surprised to find out that it had some sort of phenolic type material instead of a yellow metal bushing installed. The material is kind of similar to something you might find on a brake shoe. Well, here it is ten years later and this lightly used tractor has those bushings totally shot again. Is there some sort of aftermarket upgrade available, or does Deere propose that you just keep slapping in those composite bushings every 1000 hours or so? They don't cost all that much, but man-oh-man is it a job to get all of that heavy iron removed/disassembled/reassembled/installed. Barring any upgrade kit, has anyone ever had custom bushings made?