As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - INFLIGHT JFK-SFO. CREW REPORTED HEARING LOUD THUMPING SOUNDS FOLLOWED BY VIBRATIONS IN CABIN. LANDED ORD WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND OUTBOARD RACK SUPPLY FAN CHECK VALVE RUBBER BOOT LOOSE AND LEAKING. SECURED BOOT.