What was found
ORD - FLT 682 - WHILE CRUISING AT 41:000 NORMAL ENGINE POWER SETTING TWO AND ONE-HALF HOURS AFTER TAKEOFF, LEFT GENERATOR DRIVE LIGHT STARTED RAPID FLICKERING AND INTERMITTENT 'LT GEN DRIVE' EICA MESSAGE. TEN MINUTES LATER, LT GENERATOR DRIVE WAS DISCONNECTED. FOUND LT GENERATOR DELTA P-FILTER BOWL O-RING BROKEN IN HALF. REPLACED O-RING AND SERVICED IDG. RESET BUS POWER ON LT L-BUS, RESET GENERATOR AND PERFORMED ENGINE RUN. GENERATOR CHECKS GOOD. NO LEAKS NOTED. (X)