As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER GEAR RETRACTION A SEVERE VIBRATION CAME FROM NOSE GEAR AREA WITH NORMAL GEAR INDICATION/LIGHT IN COCKPIT. NOSE GEAR STRUT FLAT ON RETURN TO GATE. REMOVED AND REPLACED NLG STRUT SCHRADER VALVE AND COMPLETED SERVICING PER AMM 32-21-02. COMPLETED NLG T/S PER OPN 50006. CKS GOOD.