As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK. FLIGHT CREW REPORTED VIBRATION TO FLIGHT CONTROLS DURING CLIMB. NO VIBRATION INDICATION, ALL ENGINE INDICATIONS NORMAL. CYCLED GEAR AT LOWER SPEED AND ALTITUDE AND VIBRATION STOPPED. VIBRATION PRESENT WITH AUTOPILOT BOTH ON AND OFF. FOUND NR 1 INBOARD LT ELEVATOR TRIM TAB ATTACH HARDWARE WORN. REPLACED HARDWARE, PERFORMED FLIGHT CONTROL TEST/INSPECTION, PERFORMED TEST FLIGHT AND SYSTEM CHECKED OK.