It's the bolt by sway bar, 22, 23, or 24mm can't remember... For a fact bigger than 21mm cuz that's all I had at the time I did mine and went out to get the right size...
Good luck with the pumping, it'll take a little while...
bottom bolt is the drain. Top bolt is the fill hole. I always use a 15/16" wrench. Make sure you can get the fill plug out before you drain it completely.
Fill it until it overflows out of the top hole and you are good to go. Make sure you use a gear lube with LSD additive :top:
Yes thank you everyone, especially Steven. I'm running Royal Purple 75-90 in the diff and transmission. The tranny is a lot smoother now. Going into 1st is still a little notchy but up and downshifting have smoothed out immensely. I put in about 2 1/4 Quarts in the tranny.