I have transmission fluid leaking into my O.D. solenoid and it may have caused it to fail.  It sounds like there is a seal in the transmission and one inside the solenoid.   I don't know which (or both) are leaking.   As to the seal in the transmission is it installed from the outside by just pulling the old one out with a hooked probe and pressing in the new one or does the overdrive have to be apart to change it?  From what I read online, it does sound like the one in the solenoid is more difficult to replace.  Thanks