Transmission Leaks

[1963 T-Bird]

Does anyone have any theories as to why my transmission only leaks/leaves a puddle on my garage floor, after I park it overnight, but doesn't leak while it's running, whether it's parked or moving? I would think that if the problem is a bad pan gasket, and that it would leak in some kind of consistent way. But, as it is, it won't leak when running, only after I park it, and turn it off. Wouldn't there be MORE pressure, (and more of a reason to leak) WHILE it was running? Any ideas? Thanks-in-advance! Steve S.

[Karl]

Maybe it is a heat thing. When it is hot the leak is sealed and when it is cold the gap opens up.
Or maybe you are just not leaving it running long enough to see a pool form underneath.
Just some theories.
Karl.

[redstangbob]

sounds like the converter is leaking down, not uncommon for a 50 year old piece. front pump/bushing, maybe the seal or if I remember there is a check valve involved. if the leak is internal, the pan overfills and can overcome the pan gasket. JMO Bob C

[Blobird]

Check your chift regulator arm shaft or the kickdown arm shaft, thers a oring on the shaft that may leek when you park the car and the oil level in the trans vill rise . It is posible to change it if you take down the oilpan.
It has happened to me once

[1963 T-Bird]

Thank you all for the suggestions as to where to start looking! I will check it out soon,...hopefully it won't be anything too big. Have to get it up on a friend's hoist in the near future, and do some detective work. And, because I have more time than money, I'll have to wait my turn,...paying customers get priority in his garage. Guess that's only fair! Thanks again! Steve S.