What was found
NR 2 ENGINE GENERATOR DRIVE LIGHT ILLUMINATED IN FLIGHT. ACCOMPLISHED QRH PROCEDURE. ACFT GROUNDED. CREW DISCONNNECTED THE NR 2 IDG. SERVICED THE NR 2 IDG IAW AMM 12-13-21. CONNECTED IDG AND RAN THE RN 2 ENGINE. VOLTS AND FREQUENCIES GOOD. OIL LEAK DISCOVERED AT BOTTOM OF SIGHT GLASS IAW AMM 24-11-00. REMOVED AND REPLACED INNER AND OUTER NR 2 IDG SIGHT GLASS GASKETS IAW CMM 24-11-85. OPS AND LEAK CHECKED GOOD IAW AMM 24-11-00-700-803.