As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VIBRATION AT 300KT APPEARS TO GO AWAY WITH RIGHT RUDDER INPUT STOPS AT 275 WITH NO SAMC TEXT: CREW REPORTING VIBRATION WHILE CLIMBING AT SPEEDS ABOVE 275 WITH NOTICEABLE VIBRATIONS FELT IN SEAT AND RUDDER PEDALS THAT WOULD BE CORRECTED WITH RIGHT RUDDER INPUTS. VIBRATION STOPS AT SPEED BELOW 275. [06-26-07] YELLOW SYS RUDDER SERVO ACT FOUND WITH EXCEESIVE ROD END PLAY. REPLACED YELLOW SYSTEM RUDDER SERVO ACTUATOR.