What was found
ON FLIGHT 3867 THE CREW REPORTED THAT UPON SELECTING GEAR UP ON TAKEOFF THEY RECEIVED A WARNING MESSAGE GEAR DISAGREE POSTED ON EICAS. THE CREW WORKED THE CHECKLIST AND ELECTED TO RETURN TO ORD. AN EMERGENCY WAS DECLARED. THE AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE SENSOR PROXIMITY ELECTRICAL UNIT IAW CRJ AMM 32-61-01. THE OPERATIONAL CHECK WAS GOOD OF THE GEAR EXTENSION AND RETRACTION IAW CRJ AMM 32-30-00. THE AIRCRAFT WAS RETURNED TO SERVICE.