NP 205 questions

[Kiss My SS]

ok, here's the deal. My dad and I went for a test drive in the Jimmy tonight. We tested the four wheel drive for the first time and found that it is not working. It shifts into 4wheel hi and low and you can feel the gear reduction in low. The problem is that the front driveshaft isn't turning. It drives the rear wheels fine in 2 and 4 wheel. As much as I can figure, the front drive gear isn't engaging. Anyway, I figured I would check the level of lube in the t-case. Now there are two plugs on the back of the case. I assumed the top was to check the fluid level and the bottom was to drain the case. So I took out the top one and a lot of fluid came out. That seems strange. If the fluid level was supposed to be higher than the plug, then where do you fill it? I just copied the pictures from the magazine article about the 205 rebuild from and earlier post. Hopefully this might help me figure out what is wrong with my t-case. Also, what type of oil do you use in this case? Some have told me 90 weight gear oil where others have told me 30 weight. The stuff that came out looked more like gear oil. If you have any suggestions about any of these questions, I would be much appreciative. Thanks.