Mercedes-Benz W123 automatic transmission oil and leaks
What oil does the W123 automatic transmission use and how much does it take?
Use ATF transmission fluid that meets Mercedes requirements. The total capacity is about 6 litres, and about five litres come out at an oil change. The oil is checked with the engine running, the selector in N or P and the transmission warm.
How often are the W123 automatic transmission oil and filter changed?
According to one source, in the 722.122 automatic the oil and filter are changed every 60,000 km. It is worth checking the oil level, colour and smell now and then. At the change the filter and the oil pan gasket are replaced, and the gasket must not be tightened too hard so that it does not crack.
Where does the W123 automatic transmission leak oil from?
The leak often comes from the vacuum modulator, which is held by two 5 mm hex socket screws. It can be replaced without removing the transmission, and the whole part is replaced. Clean the area before the work so that no dirt gets into the transmission.
The W123 automatic's oil level is dropping and white smoke comes from the exhaust. What causes it?
The cause can be a ruptured diaphragm in the vacuum unit. The transmission oil then travels along the vacuum unit's hose into the engine and burns. Check the modulator diaphragm and the hose.