As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR5481 - STL - LANDING GEAR FAILED TO RETRACT AFTER TAKEOFF WITH LANDING GEAR DISAGREE MESSAGE ON THE EICAS. MAINTENANCE REMOVED AND REPLACED THE LANDING GEAR ELECTRONIC UNIT. OPERATIONAL CHECK OF THE GEAR EXTENSION AND RETRACTION CHECKED GOOD.