The D300 officially takes 3.9 pts. So if you did 1.75 qts., that's almost full. (Sorry, my conversion to liters is not the best. Silly American system.)
What type of oil did you use? I have read other people's posting that say to use 10/30. Some use ATF. The FSM say to use the same gear oil as the T4/T5 trans - 75/90.
I put Pennzoil Syncromesh in both the trans and tcase.
I did not have to drop the tcase. I just placed a funnel under the drain plug to catch it in a container. The fill plug (as you know) is just above the drain.
87 Comanche, 4.0, BA10/5, D44
84 CJ7, 4.2, AX15 (Formerly T5)