Strange fluid leak

[lvbizbroker]

My '80 450sl never leaked before. Until I parked it for 3 months. I just noticed a big fluid stain under the transmission, and the fluid was not showing on the dipstick. It has never leaked before, when I was driving it regularly. What would cause it to leak while parked?

[meltedpanda]

only logical conclusion if it is tranny fluid is a poor pan to engine seal, or converter plug seal