What was found
RECEIVED LEFT ENGINE VIBRATION INDICATION ON CLIMBOUT. THE INDICATION VARIED BETWEEN INTERMITTENT TO FULL INDICATION AT 3.6 IPS. ONCE IN FLIGHT, INDICATION WOULD RETURN TO NORMAL AFTER BETWEEN 2 AND 3 MINUTES UP TO 5 MINUTES. PER MANUFACTURER'S REQUEST, REPOSITIONED BOTH VIBRATION SENSOR AND VIBRATION MONITORING UNIT FROM LEFT TO RIGHT ENGINE AND RIGHT TO LEFT ENGINE. INDICATION FOLLOWED TO RIGHT ENGINE. INDICATION DIFFICULTY RESOLVED BY REPLACING BOTH VIBRATION SENSOR AND MONITORING UNIT WITH KNOWN COMPATIBLE UNITS. VIBRATION SENSOR P/N 30B3701-02, S/N 1071, ENGINE VIBRATION MONITORING UNIT P/N 241-277-000-011, SN 2511, LT ENGINE S,N CD0019, RT ENGINE S/N CD0022.