The location of a vauxhall astra transmission oil filler?

For the Astra G (Mk 4) models, the gearbox does not have a specific oil filler hole. The reversing light switch can however be unscrewed for this purpose, but as it is quite a small hole, and not in a very convenient position, it is helpful to use an oil can with a flexible spout. There is an oil level plug which must also be removed to ensure that the gearbox is not overfilled. This is located by the left hand drive shaft, and can be difficult to access. The operation should, of course, be carried out with the car on the level.