What was found
AIRCRAFT 3761, ON DESCENT INTO ANC @ FL340 NOTED BOTH POWER LEVERS MATCHED, LEFT ENGINE @ 90% N1, LEFT @ 60 % N1, AND ROLLED BACK. ACCOMPANYING AUDIBLE VIBRATION PERFORMED QRH, VIB WENT AWAY WITH THRUST LEVER CLOSED, VIB GAUGE NORMAL THE ENTIRE TIME. FA REPORTED VIBRATION. PAX VISUALLY NOTICED. CORRECTIVE ACTION: REPLACED NBR 2 ENGINE HMU, FUEL PUMP, EEC, AND BLEW OUT PS3 LINE. (LP 6350624, 0632393, 6350625)