There can be several bearing in the drive train that could create some whine. The t-case output bearing, the output from the tranny it self, the t-case input bearings could make noise. The one thing I could sujest is to put a different gear lube in the t-case and see if the noise changes (try 90-140 gear lube or if you have synthetic, change to a dino for the experment) If the noise is minor what till it gets worse, it maybe easier to find then. these 80 have a lot of whines that some vechicles have and others do not. later robbie