Trans. Fluid Leak

Within the last few days I've noticed my car leaking transmission fluid-

1990 Grand Am LE
2.5L Automatic 4 cylinder
160,000 miles

The first hint that it wasn't an oil leak was that it was quite a ways back under the car- I'm guessing a rear seal leak? I filled my fluid right away and I was about half a quart low... I've been told that when your tranny is fried it smells like rotten snatch.... Hasn't gotten to this point yet, but I'm not sure how long I can go before my car takes a crap? Does the motor need to be pulled to get to to the tranny? If so, how much does it cost to repair the seal? I can get the motor pulled by the automotive class at my college so that'll save me a guaranteed 500 bucks. What are my options, what would you recommend? Any help would be greatly appreciated!

*muah*- Sara

Check the trans pan gasket first, its a common place to look. Also check the seals where the drive axles go into the transmission, and check your cooling lines. Worst case is the input shaft seal, if thats gone you will notice a drip between the engine block and the transmission. If its the input shaft seal the transmission has to come out for it to be changed, its not too bad of a job, especially if you can get an educational program to do the labor for you.