As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DIVERSION, AIRCRAFT HAD A DULL RUMBLE FEEL JUST AFTER TAKEOFF & LANDING. RUMBLE INTENSIFIED AT VARIOUS TIMES THROUGHOUT THE FLT BUT ALWAYS RETURNED TO A STEADY STATE. NO INDICATIONS NOTED IN ACFT YOKE. FLIGHT LASTED 35 MINUTES. ACFT AIRSPEED 137 KNOTS TO 300 KNOTS. R & R THE NR 8 SPOILER ACTUATOR IAW AMM.