As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, THE NR 4 HYDRAULIC SYSTEM LOST HYDRAULIC FLUID. FLUID LOSS STOPPED WHEN HYDRAULIC SYSTEM PRESSURE WAS REMOVED. AIRCRAFT DIVERTED TO ANC AND LANDED WITHOUT INCIDENT. VISUALLY INSPECTED HYDRAULIC SYSTEM, NO LEAKS FOUND. SERVICED HYDRAULIC SYSTEM, OPERATIONAL CHECK GOOD.