Is it just a breather style vent or does the line terminate somewhere? I'm wondering if mine is either missing or disconnected. I'll also pull the cover off the bell housing but everything is dry at the front. The fluid seems to be concentrated around the top of the transfer case area.

"By the way, my husband and I own a transmission shop in Arkansas."
I saw that. If weren't so far away in SoCal I'd be knocking on your door and have you do an inspection for me.