There is some pretty good movement on my out drives from the diff housing. Very surprised they don't leak. I do use a pretty good amount of black grease on the cup shafts and that also seems to help with the out drive play. I am using 30k in the front diff though. The open bottle fell over on my work bench and did not leak out either. . This is my first truck with gear diff's; I just fill them like the video shows and I have had no issue's yet.