What was found
CREW REPORTED AT FL 380, RECEIVED A MASTER WARNING BRAKE OVERTEMP INDICATION. THE CREW SLOWED AND DESCENDED TO COMPLY WITH CHECKLIST TO LOWER GEAR. UPON CLEARING INDICATION AND RAISING THE GEAR THEY RECEIVED A GEAER DISAGREE MASTER WARNING. THE CREW COULD NOT CLEAR. THE CREW THEN DECLARED AN EMERGENCY AND DIVERTED. THE ACFT LANDED WITHOUT INCIDENT. THE ACFT WAS REMOVED FROM SERVICE. R & R NR 3 BRAKE THERMOCOUPLE SENSOR IAW AMM 32-46-01. OPS CHECK GOOD. PERFORMED ADJUSTMENT CHECK OF PROXIMITY NLG SENSOR PX22 IAW AMM 32-61-05, CHECK GOOD. PERFORMED LANDING GEAR EXTENSION & RETRACTION TEST IAW AMM 32-30-00, NO DEFECTS NOTED. THE FUNCTIONAL CHECK FLIGHT WAS GOOD. THE ACFT WAS RETURNED TO SERVICE.