Drivetrain shudder

For about a 6 months now, I have had this drivetrain/rear end chatter or shudder on my 1995 Trans Am M6 with a 105k mile 10 bolt. When take a slow, tight turn in either direction and give it a little gas (ie turning around in a Cul-de-sac) my rear end starts shaking and hopping while making a poping/clicking noise and and the clutch seems like it chatters. My clutch lets out kind of high and the tranny raises up a little bit as well. The rear end does not shake or shudder when I go straight; only when I turn. My limited slip is working correctly. When I changed my diff fluid, I did not add the GM Limited Slip Additive, but this problem probably goes beyond that.

I've replaced motor mounts with Prothene Polyurethene inserts and the transmission mount looks ok.

Not enough diff. fluid? Rear end going?