'64 Barracuda trans/shift lines question?

hello moparist overseas and in germany.

my speedo cable from my 65 barracuda is also leaking. i pulled the cable out REMOVED the drive gear but could not find the small seal. only the o-ring at the plug. i loose a lot of trans fluid daily :-( no idea how this seal looks like or where to get it..

need some help
I have all three cables on Auto -cuda trans- Leaking--
Cables are = to big dollars-
Think i may Bypass Tran pressure? ideas?
mine Drill housing at low poin fit 3/8 outlet and tee into cooler line? relieve pressure to low point.
:newb: