As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE GEAR WOULD NOT COME UP ON DEPARTURE. THERE WERE PROBLEMS WITH THE NR 2 HYDRAULIC SYSTEM. THE FLIGHT RETURNED FOR MAINTENANCE TO INVESTIGATE. AN EMERGENCY WAS DECLARED. DEFECT 437568 NR 2 HYD ISO VALVE LIGHT ILLUMINATED, LOSS OF SYSTEM 2 FLUID NLG RETRACTION ACTUATOR LINE (FLEX) . REPLACED PN DSC252C6-0200, SYS PRESSURIZED BLED, NO FURTHER LEAKS NOTED