Possible causes of oil leakage from an automatic transmission:
1. Seal wear: Over time, seals located around shafts, flanges and other parts can wear, causing oil leakage.
2. Damage to the crankcase gasket: The crankcase gasket, which seals the connection between the transmission case and the engine block, can fail over time, causing an oil leak.
3. Sump failure: The transmission sump may be damaged by impact or collision, causing oil leakage.
4. Oil pump malfunction: The oil pump is responsible for supplying oil to the gearbox. A pump failure can result in low oil pressure, which can cause seals to leak.
5. Oil cooler malfunction: The oil cooler cools the transmission oil. A malfunctioning radiator can lead to oil overheating and leakage.
6. Incorrect oil level: Insufficient or excessive transmission oil level can lead to leakage due to excessive pressure or lack of sufficient lubrication.
7. Damage to the transmission shaft: The transmission shaft connects the engine to the gearbox. Damage to the shaft may result in oil leakage from the gearbox.
8. Torque Converter Malfunction: The torque converter is the component that distributes engine power to the transmission. A faulty torque converter can cause oil to leak into the transmission.
9. Malfunction of the electronic control unit (ECU): The ECU is responsible for controlling the operation of the gearbox. A faulty ECU can result in incorrect gear shifting and oil leakage.
10. Other Causes: Other causes that can cause transmission oil to leak include a faulty oil filter, damaged shift lines, and defective sensors.