Rear Diff Oil Advise required.

Nilz

Nilz

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Hi Guys

As with some others on here, I have the issue with the back wheels locking up, I have done a haldex oil and filter change, but the issue still exists, I have changed the earth strap, still the same and also removed fuse 31 and the issue is still there.

I am going to try and change the rear diff oil.

Can anyone advise which is the best oil to go for and also how much. It only seems to be happening on the back so im presuming nothing on the front needs to be done does it??

Any help or advise much appreciated, im going to see if I can get it done this weekend.

Cheers
Nilz
 
Oil is the same as the gearbox mate... 75W90 semi or fully synth... if the haldex is engaging even with the fuse pulled I believe thats the clutch plates sticking... an oil change may not fix it straight away...

<tuffty/>
 
I did a bit of research on this. They're both 75w90 but the rear is GL5 whereas the front is only suitable for GL4. Something to do with the additives in a GL5 oil.
 
Interesting... just had a cursory search about and yeah... GL4 spec seems to be the one people suggest for the gearbox due to the GL5 spec being less syncro friendly (by all accounts)... will need to have a further read to validate this but this thread (VWVortex.com - Gear Oil: GL-4 vs GL-5?) suggests the VAG spec for 02A gearboxes is GL4 which corroborates this to a degree...

Just to be a little clearer... as Sam has said it would seem you can use a GL5 spec in the diff but a GL4 spec for the gearbox... GL5 is supposed to be more 'slippery'

<tuffty/>
 
I found out the hard way. I ordered GL4 for front and rear, only to realise (thanks to this forum) that GL5 was advised for the rear. Oh well, good to have spare!
 
I'm going to change the diff oil as i have the lock-up issue, although i'm going to buy a new controller to see if maybe the controller is duff..
 
demons uk said:
I'm going to change the diff oil as i have the lock-up issue, although i'm going to buy a new controller to see if maybe the controller is duff..
Click to expand...

Don't confuse the diff and the haldex... haldex is the clutch system that connects drive from the prop to the diff... both the diff and the haldex use very different oil... oil changes need to be done every 20k miles on the haldex... the diff and gear box typically only need topping up every now and then...

<tuffty/>
 
<tuffty/> said:
Don't confuse the diff and the haldex... haldex is the clutch system that connects drive from the prop to the diff... both the diff and the haldex use very different oil... oil changes need to be done every 20k miles on the haldex... the diff and gear box typically only need topping up every now and then...

<tuffty/>
Click to expand...

Yeah sorry didn't make that reply very clear with the lock up issue i thought it would be a good idea to change the diff oil as i've already changed the haldex and filter, i'm aware there separate units as with my last S3 the diff was a breeze to drain and fill and the haldex is a ***** :banghead:
 
So just to confirm the oil that I go for, does it need to be a particular brand or anything, is it ok to go to TPS and ask for rear diff oil if I give my reg number?

Also, how much will I need?

With regards to the rear locking up Paul, do you think the oil change will make a difference or not??
 
If getting the stuff from TPS they 'should' be able to get you the right stuff... not sure on quantity... couple of litres should be more than enough...

A diff oil change won' make any difference to the haldex issue but its not gonna hurt to do it...

<tuffty/>
 
Thanks mate, will give them a shout tomoz if i get a chance.....

Now back to the original issue.....any ideas on how further to sort the locking up issue???
 
tbh no mate... not seen any personally so can't comment... looking up is typically to do with the plates sticking or the precharge pump having a spaz... after a haldex oil change it may take a little while to free them up maybe...

Sorry I can't offer much more input on this... I believe there are some tests that can be done in VCDS to see if the pump 'works' but beyond that mate I can't really say...

Need to take one apart one day and see whats what :)

<tuffty/>
 
I think I read but not 100% sure it's about 1.6lts for the rear diff. Tuffty didn't you use the same oil in the rear as the you did in the front diff and gearbox ? As I was going to use gl4 for front and rear I have read a few people have, with no issues
 
dre_S3 said:
I think I read but not 100% sure it's about 1.6lts for the rear diff. Tuffty didn't you use the same oil in the rear as the you did in the front diff and gearbox ? As I was going to use gl4 for front and rear I have read a few people have, with no issues
Click to expand...

Yes... no idea if it was GL4 or GL5... wasn't aware at the time of the difference as I bought the stuff from GSF at the time... guess it 'should' be GL4 but I can check and its not gonna cost an arm and a leg to swap it out if required..

<tuffty/>
 
I'm not sure the rear takes 1.6L. About a litre did it for me. Haldex fluid is just the amount in the tube. Front took 3.5L.

Suction pump makes the job of the front a rear box/diff way easier.
 
dre_S3 said:
I think I read but not 100% sure it's about 1.6lts for the rear diff. Tuffty didn't you use the same oil in the rear as the you did in the front diff and gearbox ? As I was going to use gl4 for front and rear I have read a few people have, with no issues
Click to expand...

If I have it correctly, GL5 supersedes GL4 but isn't suitable for the gearbox. That said, some GL5 variants are ok in the gearbox but its safer to stick to GL4. Additionally, you could use GL4 in the rear but GL5 is better. Don't take my word for it though. Get googling ;)
 
Ok I think I will get some gl5 for the rear then, does anyone know what one to get there are a few different types 75w 90, 75w 140, 80w 140 ? I bought 4 litres well 4 quarts as its American of redline mt90 gl4 75w 90 for the front diff and gearbox. Sam I did get one of those suction pumps to do it hopefully makes the job easier as it looks near on impossible with out one
 
Paul mine remains even if you take the fuse out, so not sure its the same issue...

Will keep an eye on the other thread though, as it would be good to see if you do sort it or not.
 
Nilz said:
Paul mine remains even if you take the fuse out, so not sure its the same issue...

Will keep an eye on the other thread though, as it would be good to see if you do sort it or not.
Click to expand...

Sounds like knackered Haldex Clutch unit or ECU mate, you need a scan?
 
Hmm maybe Jo, ive already scanned the car and checked the pump, all of that is fine, no faults stored either.

Thanks for the offer tho mate :)
 
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