As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON GEAR EXTENSION AT 180KTS THE NOSE GEAR WAS VERY SLOW TO GET DOWN AND LOCKED. THERE WAS ALSO AN UNUSUAL NOISE AND ASSOCIATED VIBRATION. NOSE GEAR TOOK AN EXTRA 4-5 SECONDS TO BECOME DOWN AND LOCKED. REMOVED FROM SERVICE. REPLACEMENT OF MECHANICAL SEQUENCE VALVE FOR NOSE GEAR, #2 HYDRAULIC ISOLATION VALVE, AND THE LANDING GEAR SELECTOR VALVE WHICH FIXED PROBLEM AND ALL OTHER WORK PERFORMED. CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.