As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DEPARTURE (7,000 FEET) ATC CONTROLLER INFORMED CREW FUEL WAS OBSERVED DUMPING FROM THE LEFT WING. FUEL ASSEMETRY LIGHT CAME ON WITH A FUEL INBALANCE AT 700 LBS. AIRCRAFT RETURNED WITHOUT INCIDENT. FUEL STOPPED LEAKING EN ROUTE TO MDW. MAINTENANCE DISCOVERED LEFT WING FUEL OVERFLOW VALVE FAULTY.