300 trx 4x4

Should you be able to see the oil when you open the fill cap for the transfer case (not the front or rear diffential that takes 80wt but the transfer where you put 10W40). I opened it and could not see oil. I also could not get it to drain from the oil check screw. The gears had some oil on them but I was surprised i could not see oil in the resevior. The book says it should hold 6.4oz but i can't figure out how to drain it or check the level. I removed the screws as indicated in the book but nothing came out.