Frustrating 300E Tranny Pan Drip
 

OK...I was able to get my transmission dipstick resealed last time and no drip from there now. I put on a new tranny pan and gasket that I got from MB and now I still have a drip that seems to be building up in the back right (passenger) side of the pan gasket (I cleaned it all up and then waited an hour). It is seeping out between the gasket material and the bottom of the transmission near the back right bolt. This is the same area it was leaking from before but the dipstick was also leaking as well then. Is there a trick to this? It was torqued correctly and I don't want to tighten bolts anymore. Should I use any sealer? The Mercedes Benz transmission tech I found is the one who resealed it with the new pan and fixed the dipstick. He was very careful.

A common problem is over-torquing the pan bolts.

They need VERY little torque - maybe 7-8 lbs.

Should I try loosening them a bit?

Loosening won't work, you need to drop it, clean the gasket then do it again.

Its a PIA I know....

When you have the pan off lay it on something flat, and slide a thin card around it to check if it is flat. Then a new gasket with suggested torque, and drawing the bolts up in a staggered pattern.

Also make sure it is actually the pan/gasket that is leaking. I had what I thought was a drip from my transmission drain plug but it turned out to be a front pump seal leak that was running back and dripping off of the plug.

You might, also, want to check to make sure all the little dog eared pan supports are in place above the pan screws. I am sure there is probably a definite name for them, but I am uncertain what it might be??

Any chance the vac mod was recently removed/replaced? It is very easy to incorrectly install the vac mod seal. The incorrect installation will result in a difficult to find leak. (ask me how I know.....)

J. M. van Swaay

Wow. That's a lot of advice. Thank you! It seems to be a very basic problem. When I look up at it and clean it, the leaks starts working it's way out between the pan gasket and the transmissiion lip. I felt above and around and all was dry thinking maybe pump seals. I'll try the drain and reseal again and see what happens.