I have a leaking transmission on the 300SDL. The leak is coming from the rear servo(?) cover on passenger side. I got a new O-ring from my mechanic and replaced the one in the transmission.

All went well, or so I thought. Buttoned it up, drove it, and it is still leaking. Is there another O-ring/seal inside that I need to replace? Did I simply screw up the installation?

Another peculiar thing is that it only seems to push fluid out when driving. Don't see any drippage until it goes down the road.

I think I have solved my own problem.

It looks like you must be very careful when reinstalling the cover and push it in straight. I opened it back up today and found that the O-ring had been shaved. Must have happened during installation.

This time I slowly and methodically pushed the cover in just until I could snap the retaining ring in. Took it for a short drive and had no leaks. Keeping my fingers crossed.

The local Ace hardware made the new O-ring for a buck.

Your reply to yourself left me with a question: That is how did the Ace hardware store make the O-ring for you?

P E H

They had a splice kit. Inside it looked like they had all diameters of O-ring material, including metric. They matched the diameter and then determined the length, cut it and glued square ends to make the circle. Pretty low tech. The glue looked like regular "crazy glue."

Still no leaks.