On top of Stan's leak list, a damaged modulator can allow ATF to be drawn into the engine via the vacuum hose. It sounds like leaks are Andy's primary concern though.

When installed correctly, the seal from reservoir to sump tube and the reservoir cap itself must be leak-free. On my car anyway, the sitting cold and not running fluid level is high enough to come out of the reservoir if the cap is removed. There's a vent/equalizing hose that connects the top of the reservoir to the top of the transmission, so the reservoir level can match the rest of the transmission. That hose is flexed during fluid changes, but otherwise should suffer in normal service if all the heat shields are properly installed. Mine is a chore to get off the reservoir nipple, so much so that I leave it there and disconnect the reservoir from the tube instead on fluid changes. Some have reported leakage from that hose, worth a look for sure.

 

Schocki, I forgot to mention my B2 cover does not appear to be leaking any fresh fluid, nor in that area. It's all on the side where the reservoir is at. There's just a little bit of grime after the years. I did clean it though to see if there will be any new drips that pop up.