As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AILERON TRIM MADE POPPING NOISE AS CONTROL WAS ROTATED. FOUND BUSHING FOR CONTROL SHAFT IN PEDESTAL SEVERELY WORN ALLOWING U-JOINT TO CONTACT STRUCTURE AS CONTROL WAS ROTATED. TRIM CABLE TENSION WAS WITHIN LIMITS, NO REASON FOR ACCELERATED WEAR NOTED. BUSHING IS OILITE TYPE AND NO LUBRICATION IS CALLED FOR. (K)