Get some brake cleaner, spray it all down and clean as much gunk off it as you can. Then drive the car, jack it up and see where the leak is coming from. Axle seals are very easy to nick when putting your axles back in, I've done it many times and even though they're brand new, if you nick them they will leak. Also if you over fill the trans you can cause it to push diff fluid out of the vent on the top of the tranny. If they leaks coming from the top that's probably where it's coming from.
There are also two sensors on either side of the tranny, mine have never leaked, but I'm sure they can. That's probably an easy fix, just unscrew them and if they've got a rubber o ring replace it, if not wrap the threads in some teflon tape and it should be good.
Originally Posted by
OldMine has a leak at the bottom where the two case halves are joined. One drop seeps out about every 15-20 minutes.
This is also pretty common, especially if your trannys ever been apart for 5th get fix or anything. All that's in between the two halfs is silicone and it's easy to miss a spot when putting it back together and it will leak that way to.