As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A GEAR DISAGREE RED MSG WHEN SELECTED IN THE UP POSITION AFTER TAKE OFF. CREW ELECTED TO RETURN TO OAJ AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT THE SYSTEM USING THE AIRCRAFT MAINTENANCE MANUALS AND CHANGED THE LT PROXIMITY SENSOR UNIT. OPERATIONAL CHECKS WERE ACCOMPLISHED USING THE AIRCRAFT MAINTENANCE MANUALS AND RELEASED FOR SERVICE.