What was found
AIRCRAFT WAS GROUNDED: FLIGHT CREW REPORTED THAT ON APPROACH AT IDLE SLIGHT FUMES NOTED. AT GATE WITH APU ON PACKS ON FUMES BECAME WORSE ON FLIGHT DECK AND IN CABIN. **ORIGINAL REPORT WAS AALA202406057757** MAINTENANCE FOUND THE APU GEARBOX VENT LINE HAD EVIDENCE OF COKING AND CLEANED THE VENT LINE PER AMM 49-26-55. MAINTENANCE ALSO REPLACED THE APU GEARBOX AIR OIL SEPARATOR ADAPTER CARBON SEAL PER AMM 49-26-54 (AALA202406250245) A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ODORS NOTED.