1961 Powerglide leaks during winter storage

[1961 Jewel]

I'm sure this has been discussed before but my problem may be a little different than the usual complaint. During storage my powerglide unit will leak fluid from the left side of the transmission in the area where the shifter attaches. It does not leak out of the filler pipe where most others with this problem have stated. Is it a difficult task to solve this problem? What kind of gasket or O ring do I need?
During the driving season, it does not leak unless it sits for 2 weeks or more.

 

[Hib Halverson]

I am not a 'Glide expert but all automatics of that vintage have a manual valve actuated by a shaft that has to pass through the transmission case. There is an o-ring or a lip seal around that shaft.

The leak is caused either by a faulty o-ring or seal or a worn shaft.

You may be able to change that seal with the trans in the car, if the shaft can be removed by pulling the trans pan and disconnecting the shaft. If you can't get the shaft out with the trans in the car, you'll have to remove the trans to fix that seal.