The differential in my 39 has a good size piece missing from the end of one of the pinion gears. Probably been this way for years. I have a new ring and pinion but am hesitant to tackle the job. I assume that it would not be possible to replace just the pinion gear. The reason I even consider this is that I’m not certain how to go about replacing the ring gear. On 39, it was riveted to the carrier and I don’t know who, how or where to go about riveting on a ring gear. Is it possible to use bolts instead of rivets? Anyone had any similar experience. I would not have a problem replacing something like frame rivets but a ring gear?