As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYDRAULIC 3 LOW PRESSURE CAUTION UPON SELECTION OF LANDING GEAR TO THE DOWN POSITION AND LANDING GEAR SEEMED SLOW TO EXTEND. (FLT 4543) PURGED AIR FROM HYDRAULIC SYSTEM NR 3. REPLACED THE CHECK VALVE OF THE NLG SELCTOR VALVE AND CLEANED THE TWO WAY RESTRICTOR ON THE NLG SELECTOR VALVE IN REFERENCE TO AMM.