What was found
YYZ/CLT - FLT 5780 - AFTER DEPARTURE FROM YYZ. CAPTAIN REPORTED A NR 2 ENGINE OIL PSI MESSAGE ON THE EICAS. CREW PERFORMED A NR 2 ENGINE SHUT DOWN AND DECLARED AN EMERGENCY. AIRCRAFT RETURNED TO THE FIELD WITHOUT FURTHER INCIDENT. MAINTENANCE SERVICED THE OIL THEN GROUND RAN TEST FLEW THE AIRCRAFT. AFTER VERIFYING THE OIL LEVEL, THE AIRCRAFT WAS FERRIED TO BHM. BHM MAINTENANCE REMOVED AND REPLACED THE AFT 'F' AXIS O-RING FOR AGB HOUSING NEXT TO THE CARBON SEAL. OPS CHECKED GOOD, AIRCRAFT WAS RETURNED TO SERVICE. (X)