What was found
SEA - FLT 128 - DURING CRUISE NRT-SJC, NR 3 ENGINE DID AN UNCOMMANDED SHUTDOWN DUE TO EGT SPIKE. FLIGHT CREW ACCOMPLISHED ENGINE SHUTDOWN CHECKLIST AND CONTINUED TO SJC AND LANDED WITHOUT FURTHER INCIDENT. NR 3 ENGINE WAS INSPECTED BY MX AND THE GEAR BOX WAS FOUND TO BE FROZEN. AIRCRAFT WAS ENGINE OUT MAINTENANCE FERRIED TO SEA FOR ENGINE CHANGE. REPLACED NR 3 ENGINE. ACCOMPLISHED LEAK CHECK AND ENGINE GROUND RUN WITH NO DEFECTS NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. SHOP TEAR DOWN REVEALED THE NR 4 BEARING FAILED WHICH ALLOWED THE HPT STAGE ONE BLADES TO RUB AGAINST THE NOZZLES CAUSING THE GEARBOX TO SEIZE. THERE WAS METAL FOUND FROM THE FAILED NR 4 BEARING THROUGHOUT THE FAN AND CORE MODULE.