Only you can decide if it is worth it, but I have changed the diff oil three times now - I do it every 3 years when I service the Haldex, and it has never been a problem. I didn't like the idea of the oil having gone through however many miles and use cycles, so to me the potential benefits outweighed the possible risks. But VW sealed it up, and whether they knew what they were doing and got it right who can say.
Drilling it out and tapping it sounds scary but it really isn't very difficult. Start with a dot punch, get that right, and then slowly work up in bit sizes if you are concerned.
I went out to M8 and the plug is just a hex head stainless bolt with a copper crush washer. Never been an issue although you could always add some Blue Hylomar or something if concerned about the seal. E.g.
Once you drill it out the old oil should flush out any swarf that gets into the casing but this really should be minimal. You can always flush some more through if concerned.
Sounds like you have the correct oil. This is what I use:
Mine takes about 960ml to fill it so a litre is just enough but you don't have any spare to spill. I syringe it in to the top hole. It is a faff, but once every three years, I can live with.
Drilling it out and tapping it sounds scary but it really isn't very difficult. Start with a dot punch, get that right, and then slowly work up in bit sizes if you are concerned.
I went out to M8 and the plug is just a hex head stainless bolt with a copper crush washer. Never been an issue although you could always add some Blue Hylomar or something if concerned about the seal. E.g.
Once you drill it out the old oil should flush out any swarf that gets into the casing but this really should be minimal. You can always flush some more through if concerned.
Sounds like you have the correct oil. This is what I use:
Mine takes about 960ml to fill it so a litre is just enough but you don't have any spare to spill. I syringe it in to the top hole. It is a faff, but once every three years, I can live with.
