What was found
CLE - FLT 0288 - THE YAW DAMPER STARTED KICKING RUDDER BACK AND FORTH AT FL330. THE KICKING STOPPED WHEN YAW DAMPER WAS TURNED OFF. SHORTLY AFTER TURNING OFF YAW DAMPER, ACFT MADE 2 UNCOMMANDED ROLLS TO THE RIGHT WITH 'B' AUTOPILOT ENGAGED IN 'L-NAV, V-NAV' MODE. ACFT STABILIZED AFTER DESCENDING TO FL250. YAW DAMPER COUPLER REMOVED AND REPLACED. YAW DAMPER SYS TEST PERFORMED IAW MM 22-12-00 AND SYS CHECKED NORMAL. DFCS BITE TESTS PERFORMED AND ALL PASSED. A DFCS RIG CHK OF FLT CONTROLS PERFORMED AND ALL WERE WITHIN LIMITS. ALL SENSOR VALUES CHECKED AND FOUND WITHIN LIMITS. FLT CONTROL SURFACES ALL CHKD GOOD; INDICATIONS NORMAL WITH RESPECT TO CONTROL INPUT IN COCKPIT. (X)