My transfer case from Hades situation continues to by my Achilles heel.

Any ideas what would cause a front output shaft seal on a transfer case (NP 246) to go bad after being replaced? I just had the seal replaced about 3-4 weeks ago and the seal that was in there was supposed to be new when I got t-case, but it started leaking after a little time. Could there be something wrong with the actual output shaft/spline?

It's back at the shop now that replaced the seal a few weeks ago, so I'm waiting to hear what they have to say.