What was found
DURING CLIMB, NOTICED BOTH YOKES VIBRATING EXCESSIVELY, SIMILAR TO TAXIING ON ROUGH SURFACE. WHEN FINGER PRESSURE WAS APPLIED TO LEFT SIDE OF BOTH YOKES VIBRATION WAS PRONOUNCED. FINGER PRESSURE ON RIGHT SIDE OF YOKE RESULTED IN NO VIBRATION. AUTOPILOT ON WHOLE TIME. VIBRATION REMAIN @ 900 & 850 RPM. VIBRATION DIMINISHED DURING CRUISE @ HIGHER SPEEDS. REMOVED FROM SERVICE. C/W AIRFRAME INSPECTION FOUND #1 ENGINE AFT OUTBOARD EXHAUST FINGERNAIL BRACKET BROKEN. REPLACED IAW RD 8/4-54-26 11/1. C/W 6 BLADE RETORQUE AND PROP BALANCE. A/P PLACED ON MEL DUE TO ROLL SERVO CHATTER. MEL CLEARED BY REPLACING THE ROLL ACTUATOR. PERFORMED OPERATION CHECK FLIGHT AND PASSED. RETURNED TO SERVICE.