IRS Rear End Clonk   Wire wheel loose on splines Wire wheel adaptor nuts loose Steel wheel nuts loose Something in the boot Lever arm damper attachment bolts loose Lever arm drop link loose One or more of the 4 diff support pins broken on the chassis Drive shaft splines worn Drive shaft UJ’s worn Drive shaft/diff attachment bolts loose Driveshaft spline lock Propshaft splines worn Propshaft UJ’s worn Propshaft attachment bolts lose Diff input pinion loose/to much play Diff out