As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEN - FLT 0759 - THE LANDING GEAR FAILED TO RETRACT AFTER TAKEOFF FROM DEN. 'ABNORMAL' PROCEDURES WERE COMPLIED WITH AND THE AIRCRAFT WAS RETURNED TO DEN WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE SWUNG THE GEAR SEVERAL TIMES, BUT WERE UNABLE TO DUPLICATE THE FAILURE. THE LANDING GEAR ACCESSORY UNIT WAS REMOVED AND REPLACED AS A PRECAUTIONARY MEASURE. (X)