Is that the bottom of the bell housing in your picture? Is the fluid leaking from the weep hole there? And, have you verified that it is, in fact, tranny fluid? An easy test would be to let some drip on a paper towel to verify that it is pinkish in color. IF it is leaking from the weep hole in the bottom of the bell housing, it could tranny fluid get past the seal - or - it could also be brake fluid from a leaking slave cylinder.

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'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
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"Back off, man. I’m a scientist” ~ Peter Venkman