Originally Posted by BatteredBenz

I hope nothing I said was seen to imply there is a problem with the B1 Brake Band itself or the reaction valve itself. I have know way of knowing what's going on in that tranny. If you go to the Mercedes EPC you can sort of make out the order or position of the relative parts. The plug appears to secure the reaction valve in place, there are a couple seals around the valve and nothing to seal anything at the plug. Stands to reason the inner seals under normal conditions do a sufficient job of preventing fluid leaking that the MB engineers didn't consider sealing the plug itself.

I'd suspect one or more of the inner seals has failed or some failure in the body of the reaction valve could be allowing fluid to leak to the unsealed plug. Either way I don't yet see how it could be the B1 Brake Band itself as the problem, unless of course it could be in some strange way were the band or one of its ends wears and breaks and then jams into place or something like that, but I'd expect to remove that plug and see the end of the reaction valve, one of the ASTG transmission manuals probably shows and tells how to get the valve out/disconnected it from the Band.

I mean the MB engineers used the plug probably because they anticipated either needing the opening for assembly or for adjustment of some kind or repair.