Transmission leak.

Question is - Do our transmissions have some form of an overflow? 3rd and 5th were getting a little scratchy going into gear so i decided to replace the gear oil in my tranny. Drain it and hmmm 1/2 qt is all the drains out(but oddly there are NO leak spots on or around the drive or anywhere ive parked) . Replace it with new pennzoil syncromesh. Take it for a test drive and it shifts like butter. Stop to check air in my tires/get fuel and see a small puddle forming underneath the car. Take it home and its still leaking fairly profusely. Sticking a drain pan underneath to see how much drips out overnight. If not an overflow is there any seals that tend to go bad or anything with these trans? (5spd manual/1994) Was getting dark when i was trying to find the leak. I know its atleast midway up on the rear of the trans near where the passenger side driveshaft connects. Hoping its an easy fix. If not i get to try and break my old record of 6 h...