[ducktapeguy]

I'm planning on leaving it on even after I fix the seal because there's no reason to take it off. I see no disadvantages to having the hose connected, it can only help if the seal does fail again.

I was also curious to know whether a pressure difference was the root cause behind the fluid transfer, so I felt around the transfercase vent and I didn't see a problem. So I suspect there must be another reason for the oil moving upward. I started to remove the tranny cover to get a better access at the vent, but ran out of time and had to button it all back up to drive it. Next time I take off the cover, I'm going to disassemble the vent and add a breather hose, so I'll know for sure if the vent is plugged. But my guess right now is that pressure differential is not the primary cause of the problem. Other than that bit of info, I can't really help you.