I just had pretty much the same situation. The rear output seal on the tranny was leaking bad, then the oil went in that cavity and filled up until it started leaking out (from the top). That cavity where the t-case and tranny meet up is supposed to be dry, so i don't believe it's siliconed shut, so the oil will leak from there.
There's also a chance that the shifter extension housing up top has oil leaking from it, if it's too full. It's less likely though.