What was found
LOUD SQUEALING NOISE FROM SOMEWHERE IN AFT GALLEY. NOISE STARTED DURING CLIMBOUT. INSPECTED AFT GALLEY AREA & FOUND NR 3 OVEN VENT FAN VERY NOISY. DEACTIVATED AND DEFERRED OVEN IAW NEF 2500BI & NOISE RETURNED TO NORMAL LEVELS. CABIN PRESSURE LEAK TEST PERFORMED IAW 05-51-91 790-801 USING APU AIR WITH NO DEFECTS OR ABNORMAL NOISES NOTED. APU BLEED USED WITH NO DEFECTS NOTED. CHECKED ALL AFT GALLEY, AFT LAV DRAINS & TOILETS WITH NO DEFECTS OR ABNORMAL NOISES NOTED. AFT GALLEY NR 3 OVEN DEFERRED. PERFORMED OPS CHECK OF ALL 3 AFT GALLEY OVENS IAW AMM 25-32-03, FOUND OVEN AT POSITION G43 TO HAVE A VERY LOUD SQUEAL.