the same thing was happening to my 88 300e till I replaced the trans pan. It does not look bent but it is very slightly from overtorq. When you get the new pan follow the torque recomendations and do not exdeed it!
I chased this problem for a very long time not wanting to belive it was the pan because it looked good. Dry as a bone now! John......................

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88 W124 3.0
96 R129 119eng
06 ML350
98 ML320 sold
02 CLK55 amg