Replacing differential fluid on Type-44

[Ameer Antar]

So, I've had my tranny out of the car for a while and now I'd like to put it back. I plan to drain all the old fluid out and replace w/ Mobil 1 75W-90 gear oil. I took out the plug this afternoon, but nothing came out. Is this normal? I don't have a manual, but I guess you just top it up until it flows out, right? Is there any separate drain plug or only one drain/fill plug? I will tip the tranny over a bit to drain if it's only one plug, but I have to wait till I can get my hands on the gear oil. Any other tips/comments would be much appreciated if you BTDT.

-Ameer