Gearbox oil change process

[Doug_RS6]

I've found a pump that has all the fittings etc for a less than the official version. £45 so that's that hurdle. Next issue is lack of Vag Com. To measure the fluid temp. Would I be right in thinking that as long as I put in the same amount as I drain out then really it must be fine as long as the amount is correct currently.

[cammmy]

I have been known to be partial to a bodge but to be honest, I wouldn't do that.

Beg borrow or steal something that can read the temps or at the very least, get either an IR thermometer or an accurate brewers thermometer (tape it to the pan and then tape some polystyrene or another insulator over the base) and take the temp from the pan.

[Doug_RS6]

I have access to basic obd2 scanners but nothing particularly fancy. I could try and get hold of something more specialist but still not sure it would read trans temps. My theory was drain it when completely cold and refill it cold with the same amount. Although I've just read somewhere about it needing to be readapted after the change?

[cammmy]

A simple fluid and filter change won't require any kind of reset. That's if you have to change the solenoids in the mechatronic unit.

If you are keeping the car for a while, I would invest in something like this:

https://www.ross-tech.com/vag-com/

It's an initial outlay but in the long run it will be useful. I think trans fluid is something that's too critical to leave to guess work.

You might be fine just measuring how much fluid came out and just replacing that but the cost of tools to do it properly Vs the cost of rebuilding one of these trans (it was hard enough just finding the right seals) isn't worth it IMO.

Just to note, with the car not running, I think the level of fluid would be higher than the inspection port due to fluid draining back into the pan. So I would still follow the correct procedure, even if you decide to go by volume rather than temp.

[Doug_RS6]

Yeah I've been looking into Vag Com. Probably worth it as I like doing my own maintenance.

My intention with filling by volume was to follow the process as outlined but simply to ensure that I put the same amount in as I took out due to not being able to check the temps. So if I take 5 liters out and only 3 goes back in, I would know it was wrong so would have to keep adding or troubleshoot. I might just leave this for the VAG specialist near me. I can do the diffs myself at least going by what I've read.

[cammmy]

There is a thread on here that's good for the diffs. The transfer case and front diff share an oil supply (they also need an oil with a friction modifier). Following the normal procedure is essentially impossible with the transfer case so I did it all from the front diff and flushed fluid through a few times.

The trans is easy (if you aren't doing all the seals above the mechatronic, like I did). You just need to read the temps. I would spend the money you would pay someone else to do it on the Vag Com

[Doug_RS6]

Yes I saw about extracting the front fluid through the transfer box as it's easier to access.

[cammmy]

Yup, you 100% need a long, ball ended Allan key for it. I also had to get a spanner on the end of that for leverage. It was in tight

[Doug_RS6]

So not an 8mm Allen socket then? I'll need to try and find an Allen key lying around.

[cammmy]

0% chance of getting a socket in there. It has to be ball ended as even the Allan key can't go it straight due to the subframe.

Putting the plug back in is a bastard. I pushed it with the Allan key but that put it at an angle, so I used a screwdriver to push one side and straighten it up with the threads.

[Doug_RS6]

0% chance of getting a socket in there. It has to be ball ended as even the Allan key can't go it straight due to the subframe.

Putting the plug back in is a bastard. I pushed it with the Allan key but that put it at an angle, so I used a screwdriver to push one side and straighten it up with the threads.

I'm struggling to find hex keys with the ball on the short end. Don't suppose you know the brand that you used?

[cammmy]

You won't have room to get the short end in. You'll need to use the long end get some extra leverage. Be sure to make sure it's seated properly and supported as it took some force to crack mine.

I used these:

https://www.ebay.co.uk/itm/Bahco-BE-977 ... Sw41ddKqmQ

[Doug_RS6]

Excellent thanks. I've not looked to see the exact location of the plug.

[cammmy]

Just to the right of the R/H drive shaft

[Doug_RS6]

Excellent thanks, I have plans to work on the car this week.