What was found
ON DEPARTURE #2 ENGINE LP VIB INDICATOR WENT TO 4.0 YELLOW CONDITION. QRH DIDN'T WORK, VIB INTENSIFIED. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. PERFORMED GVI OF #2 ENGINE - NO EVIDENCE OF BIRDSTRIKE OR FOD. OBSERVED FAN ROTOR TURNS FREELY AND ALL FAN BLADES MOVE FREELY. PERFORMED MCN E770001-01, ISSUE 2. DETERMINED ENGINE VIB TO BE "ABNORMAL" PERFORMED FIM TASK 77-31-00-810-816-A PAR 1-5F. NO FAULTS OR ENGINE CHIP NOTED IN CMC. COMPLIED WITH GE LMM TASK 72-00-00-810-803, SUBTASK 72-00-00-810-011. FLOWCHART DETERMINED GE LMM TASK 72-21-00-800-806 (SPECIAL PROCEDURE 097) IS REQUIRED. PLACED ON DEFERRAL TO BE ACCOMPLISHED WITHIN 50 HOURS.