What was found
(CAN) AFTER LANDING, FLIGHT CREW SELECTED FLAP 0, FLAPS STARTED TO RETRACT BUT STOPPED AT 12 AND FLAP DRIVE CAUTION LIGHT ILLUMINATED. DURING TROUBLESHOOTING, MAINTENANCE FOUND THE RT WING FLEXIBLE SHAFT ASSY LOCATED BETWEEN THE TORQUE SENSOR AND COUPLING NEAR BS Y61.37 TO BE AT FAULT. THE CORE SHAFT COULDN`T BE ROTATED/REMOVED FROM THE CASING AND SHAFT DRIVE COUPLING, PN 744048. THE FLEXIBLE SHAFT ASSY WAS REPLACED, TORQUE SENSOR ADJUSTED AND SYS TESTED SERVICEABLE. FLEXIBLE SHAFT ASSEMBLIES ARE INSPECTED/LUBRICATED AT AN INTERVAL OF 1500 FLIGHT HOURS.