I have a 1995 e320 wagon. It's leaking ATF. I have tracked down the source of the leak, but have a question about how to proceed.
The leak appears to be coming from the rear of two circular, convex caps or plugs (1.5 to 2 inches in diameter)that are on the right side vertical surface of the transmission.
From external examination, these caps/plugs look like they would have o-rings behind them for sealing.
My questions: (1) what's behind these two caps? I have seen references to the B2 and B3 pistons in various threads that sound like this may be what I'm dealing with (although actual failure of these pistons does not appear to be very frequent on the later 124s); (2) are there o-rings behind these caps and what do I ask for if I'm ordering them?; (3) does the transmission have to come all the way out or just be dropped a little bit to get these two caps out (or at least the rear one that's currently leaking)?; (4) can either or both of these caps be removed and re-installed without making anything go weird inside the transmission?; and (5) if one is leaking, should I just attack the one that's leaking or go after both?

I appreciate any insights. Thank you.