It's a lot easier to take the tranny out with the engine. When I did my swap I couldn't get the pin out either. What I did was pull the engine out of the top and drop the tranny out of the bottom.

However later on I managed to get that bitch pin out. What I used was an M8 bolt, decent size like 3'' long. Hammer the shit out of it. It will seem like it is doing nothing for a while than 5 taps and it will pop right out.