4L80E tranny leak

I have been driving the suburban, and after about a week, I end up putting 1 quart in the tranny. I steam cleaned the bottom of the truck off, and It is leaking out of the transfercase........ I pulled the check level plug, and out came a bunch of atf....... Is there a seal that sits in the output of the transmission, or a seal on the input of the transfer case. Im just worried about burning the tranny up if I run it low one of these days. What do all yall think or know? oh, the tranny is for sure a 4L80e, and the transfer case is a np241c

im pretty sure its on the transfercase not the trans..

Output shaft seal on those transfer cases are notorius for leaking.