As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXCRUCIATINGLY LOUD, VERY HIGH PITCHED, SQUEAL BEGAN WHILE CLIMBING THROUGH 25000 FT TO 37000 FT LEVEL-OFF. TRIED SEVERAL FIXES NOTHING WORKED. ON RETURN TO AIRPORT, NOISE SLOWLY DIMINISHED BELOW 10000 FT AND STOPPED AT 8600 FT. THOROUGHLY CLEANED R1 WINDOW SEAL AND FRAME, REMOVED DC 4 FROM WINDOW FRAME AND PERFORMED INSIDE AND OUTSIDE PRESSURE LEAK CHECKS IAW AMM 05-51-24. ALL TESTS PASSED. NO CABIN PRESSURE LEAKAGE NOTED.