As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAS - EN ROUTE LAX-ORD RIGHT HAND HYDRAULIC SYSTEM QUANTITY LOSS. CONFIRMED CONTINUING LOSS OF FLUID FROM .48 TO .11 INDICATED. LANDED LAS WITHOUT INCIDENT. REPLACED BLOWN OUT O-RING ON THE HYDRAULIC DIFFERENTIAL PRESSURE INDICATOR LOCATED ON THE RIGHT ENGINE HYDRAULIC SYSTEM MODULE. SERVICED HYDRAULICS. SYSTEM GROUND CHECKED NORMAL OPERATION.