1965 Mustang C-4 transmission question

I am trying to figure out what this bolt on my 65 Mustang C-4 1965 transmission is for. (it is the original transmission) The bolt in question is on the drivers side just in front of the Band adjustment bolt. I have it circled in the picture.
if anyone knows what it is for, I would appreciate you explaining to me.
Thanks I appreciate it
Dana Wood
woody3882@aol.com
woody3882@aol.com