Where is the oil filler cap on the fiat ducato 2.8 diesel van gearbox on 2001?

You have to fill the gearbox through the reversing light sensor.Alternatively you can remove the fifth gear cover on the side of the gearbox and fit a filler plug there,making it much easier to do an oil change,which I would recommend as these gearboxes are prone to fifth gear failure.Use full synthetic oil and add a Teflon additive. Finally stick a powerful magnet on the cover,it may save you a fortune if the fifth gear disentegrates stopping all the mashed up metal going into the main gearbox.