What was found
(CAN) LOW FREQUENCY OSCILLATION FELT THROUGH AIRFRAME DURING CLIMB BETWEEN 240-270 KTS. NO CHANGE WITH AUTOPILOT ON OR OFF. ( NOTE: THIS WAS NOT VIBRATION ) HORIZ STAB PIVOT BEARINGS ON BOTH THE LT AND RT SIDE WERE REPLACED, BEARING HOUSING WAS REPLACED ON LT SIDE . ELEVATOR INPUT BEARINGS ON ELEVATOR MAST WERE REPLACED BOTH LT AND RT SIDE. FOLLOW UP ACTION THERE HAS BEEN A HARD FAILURE FOUND. COMPONENTS HAVE BEEN REPLACED. THERE IS NO FOLLOW UP REQUIRED. AC REMOVED FROM SERVICE FOR HORIZONTAL PIVOT BEARING REPLACEMENT.