I was recently doing some work on my Transfer case and decided to check the oil in it. When I pulled the fill plug a ton of oil came out. I run Royal Purple in the tranny so it was pretty clearly the source of the extra fluid.
That being said, what all needs to be done to stop this?

 

It sounds like you may have a seal between the t-case and tranny leaking putting oil in your t-case.You may have to pull transfer case and tranny to find the bad seal.