These can be a real pain in the ass, there are a couple of things you can try...
first, i would try jacking the back of the tranny up, to make sure it is level, this will help in pulling it out.
if that doesnt work, i would try to slighty easy some sort of pry bar in their, starting with the right side and "gently" prying it all the way around.
Lastly, if none of these methods work, you can use a blow torch to heat the surrounding metal on the tranny around the stud. this would help loosen it, but make sure you wipe away any wd-40 or pb blaster thats still there.
also, it is important to remember that before you separate the engine and the tranny, you have to remove the shift fork. you do this by undoing the hex nut under the starter, and screwing a bolt into the horizontal shaft. once the bolt is screwed in, you can remove the horizontal shaft by pulling it straight out and twisting and then just pull the fork loose off the throw out bearing