As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(ATB) RETURNED TO ATL DUE TO GEAR DISAGREE MESSAGE DURING GEAR-UP SELECTION WITH AN ASSOCIATED GEAR WARNING LIGHT. CREW COMPLETED QRH PROCEDURE AND DECLARED AN EMERGENCY WITH ATC. GEAR EXTENSION RESULTED IN NORMAL GEAR DOWN INDICATION. REPLACED GEAR OPERATED SEQUENCE VALVE, LEAK AND OP CKS GOOD.