As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEN/GCC - FLIGHT DIVERTED TO CYS WHEN THE FIRST OFFICER''''S DIRECTIONAL GYRO BEGAN TO PRECESS AND STICK. MAINTENANCE PERSONNEL REMOVED AND REPLACED THE FIRST OFFICER''''S DIRECTIONAL GYRO. GROUND OPS CHECK WAS SATISFCTORY. SUBMITTER STATED THIS GYRO HAD PREVIOUSLY BEEN REMOVED FROM THE GLBA SYSTEM AS A PROBLEM UNIT AND TURNED IN AS A ''''CORE'''' EXCHANGE. (X)