As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER T/O, RECEIVED TANK OVERFILLED LIGHT ON. VISUAL CHECK CONFIRMED FUEL VENTING OUT OF THE LEFT WING VENT. FUEL VENTED FOR APPROX 20 MIN. FUEL LOSS CONFIRMED OUT OF NR 3 MAIN AT 2000 LBS. TRIED TAKING TANKS DOWN TO 3000 LBS BELOW FULL AND REFILLING THEM USING THEIR ASSOC TRANS PUMPS. NO HELP. FUEL FINALLY STOPPED VENTING ON APPROACH. REMOVED AND REPLACED FUEL VENT CHECK VALVE IAW DC 10 M/M 28-12. LEAK CHECK GOOD.