What was found
(CAN) DURING APPROACH , GEAR DOWN, FLAPS 20, AUTOPILOT ON. VIBRATION, FELT LIKE SPOILERS UP. CONTROL WHEEL SHOWED 1/2 TO 3/4 (TOTAL) WHEEL MOVEMENT ROLL TO RIGHT. DISCONNECTED AUTOPILOT & AUTO THROTTLE, A AIRCRAFT, THEN ROLLED HARD TO LEFT, REQUIRED LARGE AMOUNT OF RIGHT WING DOWN TO KEEP A/C LEVEL. LANDED WITH FLAPS AT 25 UNITS, SAME AILERON INPUT REQUIRED TO KEEP WINGS LEVEL, VIBRATIONS DOWN TO & INCLUDING LDG. AILERON & AILERON TRIM CHECKED AS PER MM 27-11-00 P. 501, NO FAULT FOUND. AILERON DROOP CHECK COMPLETED AS PER MM 27-11-00 P. 513, CHECKED OK. FOUND #5 SPOILER VIBRATING HEAVILY WITH AILERON INPUT. SPOILER ACTUATOR REPLACED AS PER MM 27-61-01 P. 401. TEST FLT COMPLETED, OPERATIONS NORMAL.