As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - CREW REPORTED PRESSURIZATION PROBLEM DURING CLIMBOUT. EMERGENCY DECLARED FLIGHT RETURNED DFW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED CABIN PRESSURE OUTFLOW VALVE ACTUATOR AND GEARBOX. SYSTEM GROUND CHECK NORMAL OPERATION.