As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON REMOVAL OF THE NR 1 ENG GEARBOX CHIP DETECTOR FILTER FOUND PIECES OF O-RING PARTICLES. REMOVED AND REPLACED NR 1 ENG LUB UNIT IAW 737NG PT2 MM 79 21 01 400 801 700 STEP G, LEAK CHECK GOOD IAW 737NG PT2 MM 71 00 00 700 301 F00 TEST 3A.