ur2slo,
The half moon metal piece is called a woodruff key, you can get them at any hardware store. When the PTO driveline yoke gets worn and wobbles, it sometimes grinds the heads off the bolts and they look strange. I think if you take the bearing housing off, install a new bushing/bearing and seal it will be as good as new. You will probably have to drain the transmission first or risk getting a bath. I would bet if you did a search, you could find an
exploded view of that box (SM420), maybe even with part numbers.
Stuart.
