As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 9426 - AFTER TAKEOFF, SELECTED GEAR UP, MAINS RETRACTED BUT NOSE GEAR HAD A LOUD CONTINUOUS BANGING NOISE WITH ON INDICATION OF GEAR UP OR DOWN. SERVICED OIL AND NITROGEN OF NLG STRUT. PERFORMED EXTENSION / RETRACTION TEST, OPS TEST GOOD.