For the life of me I can't get the transmission on my 124 to stop leaking at the pan gasket. The leak is a small, slow drip that happens mostly when it is hot. I'm on my second pan gasket (after a recent filter/fluid change) and both times I torqued it to spec in a crisscross pattern and both times it leaked almost immediately at the front right corner. I've started to try to tighten only that corner to see if I can get it to stop and after a couple of pretty good "additional snuggings" it's still leaking. I'm afraid if I tighten anymore I'll split the rubber gasket and then it will leak like mad. My guess is that somehow my pan has gotten warped and I need to spring for a new pan and (yet another) gasket. Has anyone ever had this problem before or is there something I'm missing?

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

A piece of glass is almost perfectly flat (do not use any of your wife's or
girlfriend's mirrors)
Take the gasket off , clean the Pan mating surface,sprinkle talcum powder
over the piece of glass,invert the pan onto the glass,and look for an area
on the rim of the pan without powder on it. (Not difinitive , but a good
diagnostic)

Upon engaging my brain... Look closely at the underside of your tranny , at
the mating surface between the tranny and the pan.Are there any
irregularities in the area of your seepage?

The reason I ask, on my W126 there were a couple of other spots leaking that initially appeared as a problem with the pan gasket.

One was the cooler line had worn through and the fluid ran down the line and leaked in that very area. The rubber cushion in the clamp had disentegrated.

The other was the dipstick grommet. The bolt holding the upper portion of the dipstick was loose and vibration caused leakage around the grommet.

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Sam

84 300SD 350K+ miles ( Blue Belle )

I'm sure there is a leak around the pan gasket because I have done several cleaning sessions followed by short drives to see where it leaks. All the surrounding areas are dry. I even stuffed a rag up above it to make sure the leak wasn't dripping from above. When I replaced the pan gasket last time I throughly cleaned and checked both mating surfaces and everything looked pretty clean. One potential cause though now that I think about it is the fact that the paint on the pan is peeling off pretty bad. Hmmmm...I wonder if there is an irregularity on the lip of the pan that's keeping it from sealing properly. I'm going to check it tonight and will report back. Thanks for your advice.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

Over time, loosening and tightening the bolts will warp the pan a little at the lip. You can do the talc powder test and try your best to fix it with a hammer, or you can buy a new pan.

Well I removed the old pan with the intention of trying the glass trick to see if it was flat. Unfortunately there are metal tabs at each corner that stand proud of the mating surface so I couldn't properly check it. In the end I just bought a new pan and gasket. The good news is the pan was relatively cheap and it did reduce my leaking so it definitely was a bit warped. The bad news is that I still have a small leak above the pan that I hadn't noticed until I fixed the leaking pan. I'm thinking of trying a transmission anti-leak additive but am never totally comfortable putting that sort of stuff into an expensive MB transmission. I guess I'll let it leak a bit more before I make up my mind to do it. As the owner of a couple of English cars oil leaks are not new to me. Thanks everyone for your suggestions.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

put stop leak in my tranny. it simply softens your rubber parts so that they swell up. very short term fix.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.