turned out to be the CV joint in the driver's side rear half shaft. I shopped around. Coz has some passenger side OEM half shafts and Z1 has both sides but Z1's are not recommended for higher HP Z's. Both Coz and Z1 want $620 to $650 a shaft! I found both half shafts (available to order) from Autozone of all places. They are made by TrakMotive in California and are supposed to meet or exceed the performance of the OEM half shafts. They go for only $120 and $160 so I ordered both. My plan is to remove and rebuild my originals, install the TrakMotives and see how long they last.
Half shaft info. I heard some clicking going on and it - Zblackbeast16:51:45 06/08/19