What is leaking on my transfer case?

[DropTopDon]

Had the angry sparrows so I pulled my driveshaft. I noticed this on my transfer case, what seems to be leaking?

 

[hear]

there's an o-ring or seal under the selector switch, looks like a reasonable suspect based on that picture. But it also could be from the transmission blowing onto the t-case.

 

[Irun]

I'd start by cleaning things up, i.e. de-grease. That will help you better identify the leaking location/s.