What was found
A DIRTY SOCK ODOR OCCURRED STARTING T/O ROLL AND WAS GONE AT 20,000 FT ON CLIMB. NO ODOR DURING FLIGHT. THE ODOR REAPPEARED ON DESCENT AT 15,000 UNTIL LANDING. IT WAS DETECTED THROUGHOUT THE CABIN AND COCKPIT. ACFT GROUNDED. ACCOMPLISHED CABIN ODOR T/S IAW FIM 05-51-TASK 814. DURING INSP OF APU DRAIN FOUND OIL CONTAMINATION AT MIDDLE DRAIN FOR LOAD COMPRESSOR REF AMM 49-15-11. REPLACED APU. REPLACED BOTH RECIRCULATION FAN FILTER IAW AMM 21-25-01, APU OPS CHECKED GOOD, NO LEAK NOTED RAN BOTH PACKS NO ODORS NOTED.