transmission leaking fluid

I had this problem with my 727 years back. It only leaked after it had sat for a day or two. The rail around the pan was wet, I couldn't tell where it was coming from. I'd wipe it down and the next day it'd be all wet again.

Turned out to be the seal around the neutral safety switch was no good. I replaced the seal (an o-ring, if I remember) and the switch, it hasn't leaked since.