We've had a SMALL transmission fluid leak in our 2002 Escape since about Thanksgiving... Our mechanic is retired with a nice shop behind his house and he's replaced and tightened various things. It started with a leaky rear seal which he replaced, but we noticed it leaking right after that. The seal was now dry, so on the recommendation of the dealership he replaced some kind of axel and another seal (sorry, not a car expert here). It kept leaking. Just a spot about the size of a silver dollar under that cylinder-shaped thing near the front. He then replaced the dip stick o-ring, and for a few days we thought the problem was gone. But when I took the car on a longer drive it was leaking again. I think it might be leaking less than it was. We don't drive it much, just around town usually, but it seems to have gone from a constant drip to an intermittant drip.
Actually, the CarMax papers we got with it (we bought it in April 2010) indicated they're replaced a seal, too.
Our mechanic can't think of what it could be. He says the transmission seems fine, and it runs great. When he puts it on his lift he can't see anything dripping from anywhere. But driving it we'll occasionally smell transmission fluid smoking as it drips onto hot car parts, and see that annoying little drip hanging from the cylinder, and would love to get to the bottom of this.