According to the regulations for the American market, the oil change in the front gearbox is required every 30,000 miles or 48,000 km.
The oil must be poured with the original Matic-S as in the service manual
1. Remove the plastic protection:
Below it we see the Reduction Gear itself and the engine
2. Unscrew the two plugs. The bottom is the drain, the top is the liquid level.
3. Drain the old oil. Mine was an unhealthy brown color. There were no shavings. The plugs have magnets.
4. Tighten the bottom plug and fill 1.3-1.4 liters of fresh oil with a syringe through the top plug. Screw on the top plug.
5. Put the protection in place.