The piece on the axle came out of the final drive/diff same difference.Differential? On a single-wheel drive system? Rear drive bearing maybe? But even than, I've never taken the rear end further apart than just removing the rear wheel; and only have replaced just the rear wheel bearings once but they were REALLY bad at the time. Can't tell what that picture is showing (a bearing and spacer maybe?) but I'm sure someone will be able to help.
The final drive service is on my list of things to do while I've got it.Hi, spacer coming out with the shaft not a problem, it's job is to center the wheel in the swing arm,and keep the weight and side loads off the final drive bearings. The early Silverwings had a few spacers that were to short and would destroy the big bearing in the final drive. To long of a story to say how I know that. A quick check would be pull the fill plug on the final drive and see if it has any metal particles in the oil. G