What was found
THE NR 1 ENGINE IDG WAS RECENTLY REPLACED DUE TO FREQUENT SERVICING HISTORY. THE NEW IDG HAS A FREQUENT SERVICING ISSUE WHICH REQUIRED THE ACFT TO BE REMOVED FROM ETOPS ROUTING. ACFT GROUNDED. ACCOMPLISHED IDG UNSCHEDULED REMOVAL FOR CAUSE FILTER INSPECTION ON REMOVED UNIT, NO DEFECTS NOTED IAW AMM 24-11-11-080-801. COMPLETED R & R OF NR 1 IDG IAW AMM 24-11-11-401. COMPLETED OPS AND LEAK CHECK. NO LEAKS NOTED, OPS CHECKED GOOD. NO LEAKS NOTED ON NR 1 IDG AIR/OIL COOLER AND OIL SUPPLY LINES AND FITTINGS BEFORE OR AFTER IDG CHANGE. IDG CHANGED FOR PRECAUTIONARY MEASURE IAW THIS TSR.