What was found
AIRCRAFT WAS GROUNDED: DIRTY SOCK SMELL FROM TOP OF DESCENT TO LANDING. MAINTENANCE DETERMINED THE SOURCE OF THE ODOR WAS A LEAKING YELLOW / GREEN HYDRAULIC POWER TRANSFER UNIT IN THE RIGHT MAIN LANDING GEAR WHEEL WELL BEING INGESTED INTO THE APU. THE YELLOW / GREEN HYDRAULIC POWER TRANSFER UNIT (PTU) WAS REPLACED PER AMM 29-23-41. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED. MAINTENANCE CLEANED THE APU AIR INTAKE PER TASK CARD 26T31049006 AND ACCOMPLISHED A DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYSTEM PER TASK CARD 26L00021004.