I am in the middle of a rear disk brake conversion.... I finished putting the axles back in and was cleaning out the bottom of the diff when I found this! I believe that it is a shim for the small gear that the large pin is inserted through. Is it possible that it fell out while I was pulling the axles or has it been riding around at the bottom of the diff ever since the PO installed the Eaton LSD.
Any suggestions on how to put it back where it belongs?