I did check for clearancing on the inside of case and did not see any marks. The gear teeth all look uniform and unworn.
There was no play in the shaft or tailshaft bearing.
I will say that my growl does seem like it's coming from the T case.
I did a search for "Growl on Deceleration" and found a bunch of posts on a variety of forums.
Almost all were solved with an SYE
Funny thing. In my search I found this old thread I made about my last Jeep.
Ujoint fixed that one for a while. SYE eventually cured it