What was found
AFT CAST SURFACE OF DRAG PIN ASSY THAT IS PART OF M/R GEARBOX CONTACTED YOKE OF ISOLATION MOUNT. CONTACT DUE TO EXCESSIVE CASTING MATERIAL AFT OF BEARING BORE. COMPONENT SHOP RECEIVED AN ISOLATION MOUNT FOR REPAIR THAT HAD FRETTING/CONTACT MARKS ON YOKE. MARKS WERE CONSISTENT WITH DRAG PIN RUBBING/CONTACTING. BASE THAT ISOLATION MOUNT RECEIVED FROM INFORMED, & DRAG PIN & GEARBOX WERE REMOVED & FORWARDED TO US. WHEN RECEIVED DRAG PIN, WAS APPARENT THAT DRAG PIN BEARING BORE WAS NOT SYMMETRICAL IN CASTING.