As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#1 IDG AIR/OIL COOLER FOUND TO BE LEAKING OIL. GROUNDED - YES. PER B737-900 AMM 24-11-21-200-801, OIL STAINS OR LEAKAGE ARE NOT PERMITTED, IDG AIR/OIL COOLER MUST BE REPLACED. REMOVED & REPLACED #1 IDG AIR/OIL COOLER PER AMM 24-11-21. OPS CHECK GOOD. A/C OK FOR SERVICE.