the c6 in my 89 in sig leaks, only after setting for more than 2 days. I drive it every day or every other day and it does not leak a drop. Researching it i have come to the conclusion that the convertor is draining back filling up the transmission case. I have read about a convertor drain back check valve, Is this in the actual pump, or in the cooler line? Seems i have read several different theories, but nothing other than to check or replace this valve.
Transmission shifts great and fluid looks good.

Can someone point me in the right direction?

 

Anybody?

 

Try a new seal on the dipstick tube.

 

good idea, thanks

is the "convertor drain back" normal?

 

The check ball is in the valve body. Not normally known to go out.

 

probably just sticking or not completely sealing?

good excuse to slap a shift kit in?