As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD INFLIGHT T644/14FEB - COULD NOT RETRACT LANDING GEAR. RED UNSAFE INDICATION. RETURNED TO ORD AND LANDED WITHOUT INCIDENT. REPACKED NOSE LANDING GEAR STRUT SEALS AND REPLACED LOWER TURNING TUBE BEARING. SERVICED STRUT. SYSTEM GROUND CHECKED NORMAL OPERATION.