Your transmission is a 722.607 and requires dealer-specific fluid. You must've gotten some misinformation.

If MBDOC says you don't have a TC drain plug, then you don't have one, and need to use the cooler line method of completely exchanging the fluid, or do partial drain and refills by draining the pan multiple times as discussed in our PMs.

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95 E320 Cabriolet, 169K