As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT ATTENDANTS REPORTING CONTINUOUS LOUD SQUEAL FROM R2 DOOR. IT BEGAN 10 MINUTES AFTER DEPARTURE AND HAS PROGRESSIVELY BECOME LOUDER DURING FLIGHT, PRESSURIZATION IS NORMAL. FLIGHT ATTENDANTS STATE IT DOES AFFECT COMMUNICATION. GROUNDED - YES. REMOVED AND REPLACED OUTFLOW VALVE PER AMM 21-31-03. OPS CHECK PER AMM TASK 21-31-00-710-801 AND TASK 21-31-00-700-802, GOOD. NO SQUEAL DETECTED WITH AIRPLANE PRESSURIZED TO 4.0 PSI.