The transmission is in many respect similar to the Chief model, except for the chain transmission, and there is a R&O video that KIWI Thomas has made that might explain some of the workings and pitfalls to avoid with the transm. There is a few details where I personally doesn't agree with him, that I explained in an earlier post, but not a big issue.
https://www.youtube.com/watch?v=_HK06bLXYDE
https://www.youtube.com/watch?v=-_RJoLRAYRs
https://www.youtube.com/channel/UCrvPYmxwrLmuFwQlIzJdNVQ/videos
He is showing an overview on a -31 101 here:
https://www.youtube.com/watch?v=mctxSFiLOyI