In the past few days i've gotten a bit of a whine coming from what sounds like the rear diff.
35-40mph in 3/4/5 at very low throttle there's a whine
60-70mph in 5th/4th you can hear it as well
As soon as you throttle in the whine stops.

The car gets tracked pretty heavily.

T-case was built about a year ago, running redline heavyweight shockproof.

Has anyone else had an issue like this?

 

My car sounds like that but I bought it built with low mileage.... was told it was normal by shep...

 

Wow.. well my buddy's shep trans sounds exactly like mine now that I think about it. Adding to it, I just put this transmission in not more than 3 weeks ago, maybe I never really paid attention to the noise.

 

I had the pinion bearing go in mine. Just started getting louder and louder.
Jon at TRE says he is beginning to see more of this.

I put mine with all 4 off the ground in 4th gear and the source of the noise was pretty obvious.

 

If it has started to make noise the back lash has changed. At least it is something to monitor and attend to if it gets worse. After servicing, if you have that done, it may still make noise because the gears have worn together and now the setting is not exactly the same.