As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXPERIENCED A DIRTY SOCK ODOR DURING TAXI OUT. RETURNED TO GATE. FOUND AN OIL LEAK AT OIL COOLER FLANGE. EXTERNAL LEAK DRIPPED ON TOP OF INTAKE DUCT AND WAS BEING INGESTED INTO APU INTAKE PLENUM. HIGH POWER ENGINE RUN. REPLACED THE RECIRCULATION FILTERS. NO FURTHER ODOR.