Hi folks. A thorough search turned up some threads discussing this, but the configurations were different from my '91 500SL. I have a leak in this area in the front driver's side area of the trans.



I replaced the O-rings in the kickdown solenoid, but I then discovered the leak is coming from above, around the overload protection switch. It seems to be running down the back side of the plate that the switch is mounted through.



The switch itself is fine, it doesn't leak between the plastic and the case.


I replaced the little O-ring on the end of it, but I'm still getting fluid in this hole that the switch came out of.



The fluid is then leaking past the seam where the threaded part meets the plate. The seam doesn't have any kind of seal, so I'm assuming it's not meant to hold back pressure, and there isn't supposed to be fluid in that hole.





The diagrams I've been able to find online and the dealer parts counter has don't describe what's going on in here. If I pull out the lock ring, and unscrew the hex nut, is there a seal in there that could be causing fluid to get in there? I'm a bit out of my depth here, and don't want to mess up some adjustment or release a bunch of small parts that will turn my leaking trans into a broken trans. Does anyone know if this is a possible point of leakage, and what is required to fix it?