Yeah, the early transaxle components, cones, sprokets, discups and such were held to shafts with roll pins. Someone figured out that it was better to key the components to the shafts and hold it all tight with a nut. It proved easier to repair the transaxle as well. Your machine should be held together with the nuts
I have been a Dixon owner (and fan) since 1985 when I bought my first machine. My local dealer took me under his wing (had to to get rid of me) and taught me how to adjust the transaxle and I have taught others how to as well. I like the "classic" axle, but not the Z-Drive. I have worked on them but my dealer almost refuses to. They are not easy to adjust and will eat up tremendous amounts of time. I am in the Paducah area alltough I know that is a long way to drive for help.
By the way, I am looking for a very early Dixon; the older the better.