As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DRIVE LIGHT ILLUMINATED. DISCONNECTED DRIVE. GROUNDED - YES. REMOVED/REPLACED/TESTED #1 ENGINE IDG PER B737-800 AMM 24-11-11-000/400-801, 71-00-00-800-811-F00. GROUND VERIFICATION REPAIR CONFIRMATION SUCCESSFUL PER FIM 24-11-801. LIBERATION OF VALVE CAP LIKELY RESULTED FROM EXCESSIVE CAP SCREW TORQUE. NO DEFECTS NOTED.