Update: Thanks to the service manual, I was able to pull the transmission and rebuild it with new front and rear bearings, new synchronizer rings, and a small parts kit including needles and thrust washers. I also installed a new shift bushing and pin. While I was at it, I pulled the differential and changed the gears from 4.11 to 3.55. I also changed the carrier and pinion bearings, front bushing and seal, and finally the rear axle bearings and seals. Although it was a lot of work, I have to say much of it was easier to deal with than the old 4-cyl Chevys I'm used to wrenching on. The mechanics and designers must have had a meeting at some point between the 20s and the 40s. :)