As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK - CREW REPORTED HEARING LOUD BANG DURING GEAR RETRACTION AND CENTER HYDRAULIC SYSTEM PRESSURE LIGHT ILLUMINATED. FLIGHT RETURNED JFK LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED HYDRAULIC PUMP REGULATOR SHUTOFF VALVE. SYSTEM GROUND CHECK NORMAL OPERATION.