jrhackett,
You might want to edit punctuations in your post - to make individual sentences.
Jerry knows more about Hydra-Matics than anyone here.
You might/might-not be interested
in this long-winded, step-by-step rebuild of a 1954 Hydra-Matic transmission. Unfortunately, it does not show the complicated shift-linkages.
I cannot find an illustration of the shift linkages - maybe someone will post a web-link?