I got a new socket wrench with a longer handle on Saturday and that did the trick. My transmission was definitely overfilled because fluid started pouring out the second the fill bolt came off. I made a mess of things, but hey, I've never changed fluid under the car before.
Buying the Amsoil MTF has been without a doubt the best $24 I've spent on this car. Within a few minutes I could feel the shifting get smoother. I can still feel some notchiness going into third, but there's no actual resistance. I haven't grinded and it hasn't popped out since. It's not perfect, but it's so much better than before. Well, I'm happy for now.
