I'm about to clean my GST diff so I can toasteroven it

, and was wondering what kind of cleaning everyone did before sticking it in at 200. WD-40 would probably light up, unless it sits for a few days and I don't want to use soap because of the barings. Also when I rebuild should I use assembly grease or the diff fluid for the outer gears? Why is there a hole in the cup for the center shaft diff? Thought that was a closed system. Does the nemesis center shaft diff cup have a hole in it also?
How many people have steep hill climbed with there GST? The runway isn't the greatest, haven't tryed but the truck takes off fast. I was thinking 300k center, 60 rear and 50 front but might go 120k to try and keep the nose down if I get trigger happy.
Thanks.
edit
I don't have any degreaser that I can find, and I'm feeling lazy and not going out untill tomorrow.