What was found
DURING CLIMB, 20000 FEET, 295 KTS, B AUTOPILOT IN USE. AIRCRAFT WAS IN SMOOTH AIR WHEN A SHORT KICK WAS EXPERIENCE. RUDDER KICK WINGS REMAINED LEVEL AT ALL TIMES. NO RUDDER INPUT BY PILOT WAS NOTED. REMOVED AND REPLACED RUDDER PCU ENGAGE SOLENOID PER MM.