Hello husker gleaner, I would repeat what the other guys said about checking that 1 1_4" main dr. shaft. Check so it is straight, check the key ways, and bearings, and sides of the machine for cracks around the bearings. I have also seen where guys would use one correct and one wrong drive arm. The older machines bushings were smaller then the latter machines so the arm also have to match. You probably know all of this already, so I'll shut-up. Where are you from in husker countryIJIJ I guess I am also a husker gleaner man. Thanks,