Technical 727 Pushbutton... Again

Thanks to everyone who answered to my last thread.
So I had the tranny shifting well, sitting still, but once I drove it around then Park started to not engage. Back to playing with the cables.

My question now, I know the later 727s and 904s have the kick-down shaft seal that can be replaced from the top. But I have a 63 transmission with a leaky shaft seal. Does the whole valve body have to be pulled or can it be done at the top?

 

I did one about 40 years ago, seems like the pan comes off, then the shaft is unhooked from inside - your shop manual has step by step sequence

 

A bunch of factory manuals available here.
http://www.mymopar.com/index.php?pid=109

 

Thanks for the resources guys. My 60s motor manuals don't go that in depth.