What was found
MAGNETIC RETRIEVAL TOOL PRODUCED A METAL PIECE, .870 INCH BY .210 INCH BY .100 INCH FROM CRANKCASE SUMP. INVESTIGATION DISCLOSED NR 3 MAIN BEARING WAS LOOSE IN CRANKCASE AND WAS THE SOURCE OF THE METAL FRAGMENT. DISASSEMBLY SHOWED NR 2 MAIN BEARING WAS WORKING IN CRANKCASE ALSO. THROUGH-BOLT TORQUE HAD BEEN CHECKED 30 HOURS PREVIOUSLY AND WAS FOUND BELOW SPECIFICATION. SUBMITTER STATED ASSUMPTION IS THAT WAS THE CAUSE OF THE BEARING FAILURE. DISCREPANCY WAS FOUND DURING TOP OVERHAUL PROCESS.