How do you top up gearbox oil in a peugeot 407 diesel?

To top up the gearbox oil in a Peugeot 407 diesel, first ensure the vehicle is on a level surface and the engine is off. Locate the gearbox oil filler plug, usually found on the side of the gearbox. Remove the plug and use a funnel to add the appropriate type of oil until it reaches the bottom of the filler hole. Finally, securely replace the filler plug and check for any leaks.