What was found
AFTER ROTATION, CREW NOTICED A VIBRATION. NR 3 ENGINE VIBRATION INDICATOR DISPLAYED HIGH. ALL OTHER ENGINE INDICATIONS WERE NORMAL. VIBRATION DISAPPEARED AFTER REDUCING BELOW TAKEOFF POWER SETTING. OPERATED NR 3 ENGINE AT IDLE THRUST FOR REMAINDER OF FLIGHT. REVERSE NOT USED ON LANDING. R & R NR 3 ENGINE IAW AMM 71-00-02 AND TASK CARD 71-001-00-00. OPS & LEAK CHECKED GOOD IAW MM 71-00-00, TEST NR 8 AND TASK CARD 71-001-00-00. ACFT OK FOR CONTINUED SERVICE.