Ok. there have been a number of people with the clicking noise the 'TINK' coming from the rear wheels. In this video you can here the noise for comparison and see the fix.
My noise is completely gone.
I started
a thread introducing my problem and ended up getting linked with the
thread that TAG UR IT wound up finding for a dealer fix.
TSB# 09-04-95-001B
Washer: 20825083
Nut: 13217120
The TSB is documented but many of us are modified and have no warranty.
Easy fix for the DIYer.
Special thanks to Maureen and the folks at Rogers Chevrolet for getting me the parts so quickly. They really do come through quickly for me every time.
The video is kinda long and has a lot of stuff for the total newbs but gives a perfectly accurate showing of what exactly the procedure is and does.
EDIT: The TSB says to tighten the axle nut to 199 ft lbs. In my vid I tightened to 159 per advise from a third party. I'd go with 199 to be safe.