# Diff Oil



## phaetonjohn (Oct 24, 2014)

Ok, so I'm doing a diff oil change on the front, rear, and transfer case diffs.
BUT!

What oil do I use? I've read on the internet that G 052 145 A2 has the friction additive thing for the locking aspect of the diff. (I'm far from an expert so don't go bashing me for my inaccuracies lol)
But the dealer gave me G 052 145 S2. Not sure if this has the locking additive thingy or not. Will I be ok to dump this stuff into the 3 diffs?



















I'm doing this Wednesday as I have access to a hoist then, so any replies before then will be much appreciated 

-John 


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## phaetonjohn (Oct 24, 2014)

Or maybe the term is FRICTION MODIFIER? Or FRICTION ADDITIVE? I'm not sure.


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## s2kvondeutschland (Mar 19, 2011)

I did mine recently, but did not use OEM oil. 

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## phaetonjohn (Oct 24, 2014)

s2kvondeutschland said:


> I did mine recently, but did not use OEM oil.
> 
> Sent from my XT1650 using Tapatalk


Was there anything in regards to a friction additive in the oil you Used?


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## s2kvondeutschland (Mar 19, 2011)

I used Castrol Syntrax 75W-90, which is friction modified. I have no diff grumble even on full-lock low speed turns. 

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## phaetonjohn (Oct 24, 2014)

s2kvondeutschland said:


> I used Castrol Syntrax 75W-90, which is friction modified. I have no diff grumble even on full-lock low speed turns.
> 
> Sent from my XT1650 using Tapatalk


Ok, well time will tell to see if I get a grumble or not!! I'll save the old oil jus in case! 


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## Phaetonlvr (Feb 26, 2013)

Earlier this year when I had to replace the leaking rear trans seal (that's actually part of the center diff) on my '04 W12, I had to refill the center diff with fresh gear oil. I know the W12 has the 5-speed trans but it still uses the same gear oil in the diff. According to the Bentley manual it needs to be part# G-052-145-A2 but VW dealer told me that this part# is now superseded by part# G-052-145-S2 so I used that and now, 3k miles later, it's still fine, no issues. Btw, it's viscosity rating is SAE 75W90 and it's pretty pricey.


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## s2kvondeutschland (Mar 19, 2011)

I believe you have the right oil. I see S2 listed for transfer cases and differentials, whereas the A2 is only listed for differentials.


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## phaetonjohn (Oct 24, 2014)

Stephan and Joel,

Thank you so much for your information!! I truly appreciate it.
I got the oil at around $30 a litre, so I'm not complaining too much 

Thanks again!!!

-John


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## autoecostyle (Oct 23, 2016)

*Problemen met Phaeton*

Goedenavond JorgsPhaeton
ik zoek iemand van problemen die opgelost worden met mij phaeton.
Kan jij mee helpen.


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## phaetonjohn (Oct 24, 2014)

Ok so the rear diff is changed. The fill plug didn't want to come out and was starting to become rounded. Used a torch to very slowly heat up the diff and the fill plug came right out. The oil that was in it was almost like new. Perfect colour and smell, and zero contamination.
Tomorrow I'll see if I want to do the front or centre diffs.


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## s2kvondeutschland (Mar 19, 2011)

You'll need some tubing that is the right combination of skinny/stiff/flexible and some patience for the other two. 

Good luck!

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## steveskinr (Oct 31, 2007)

The bottle looks familiar. But I can't check it now.

Some thoughts I posted in a different thread.

11-22-2014 01:04 PM Edit / Delete #24
I suggest that the moderators change the title of this thread so that "differential" is spelled correctly. It will get more hits when it is searched for.

Bear in mind during the tedium that follows, that the front and center diffs were sucked out and thus more likely to be contaminated.

Color/Colour

The difference in colors could not be ascertained in a clear cup, two inches deep and two inches wide. You need to look at the color with about a millimeter in the bottom of the clear cup. Sorry for mixing metric and English.
The front and center differential oil is redder than the rear diff oil. 
The rear diff oil is greener. The original oil is very slightly yellow.
I put a drop of each on white paper and could not ascertain any difference.

Smell

Three noses. 
My wife got a headache immediately on sniffing them so she didn't get to calibrate her nose very well. She thought the rear was strongest but it was the first one she smelled. 
I congratulate the mechanics who contort themselves and deal with all the noise and smells.
My son thought the front had the most smell. He only got in a few sniffs though.
The smell of the new oil is also quite pungent. 
I found the center diff oil to have the least amount of smell, consistently. If I were relying on smell alone, I would wonder if it was the same oil as the front and rear. I partook of ten rounds of sniffing over two hours during which I dedicated my body to science.

Viscosity

This was easiest to ascertain with a millimeter in the bottom of a clear cup.
The rear was more runny.
The front, center and new oil were more sticky. 

Conclusion, but beware, a tribologist - I am not

On the other cars, I will change the oil in the rear diff at a minimum. It had a significant change in viscosity. I can't tell if the redder (front and center/centre) or greener (rear) oil shows more degradation based on color. But if I had to guess, I would guess that the greener color was correlated with the increased runniness. I am sorry to be so crude (pun observed after the fact) but to say something has increased viscosity is ambiguous in common parlance.

I might change the front diff fluid, since it took an hour. It didn't seem to have had a breakdown in viscosity though.

I think I will wait for quite a while to change the center diff oil since it took two and a half hours and didn't seem to have any change in viscosity.


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## phaetonjohn (Oct 24, 2014)

Hey Steve,

Thanks for the info!! Yeah, my rear oil looked and smelt like new. No contamination either.

The slight growling I had coming from the back during a full lock turn in second gear is less now.
It look over an hour and a half to change the rear diff oil.
Errrrrrrrrrrrrr

-John 


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## phaetonjohn (Oct 24, 2014)

Sit rep.

Unable to locate the drain plugs for both the centre and front diffs.
Unable to access the fill plug for the centre diff, and unable to remove fill plug for front diff.

Given the quality of the oil that came out of the rear diff, I think it's safe to say that the front and centre should be fine.

-John


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## s2kvondeutschland (Mar 19, 2011)

There are no drain plugs for the front and center differential. I eventually used a syringe with nylon tubing. 

I was able to use a hex key on the front. Or maybe I used a hex bit on a ratchet. The center was a pain. It involved a floor jack and removing the mount bracket. 

I did everything on jack stands, including the transmission filter. 










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## StevenFT (Jan 26, 2012)

Stupid question:

Do you have the jack stands on the pinch weld or on the lifting points?


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## s2kvondeutschland (Mar 19, 2011)

StevenFT said:


> Stupid question:
> 
> Do you have the jack stands on the pinch weld or on the lifting points?


On the pinch welds with hockey pucks cut and used as adaptors. I used my floor jack on the factory lift points. 

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## invisiblewave (Sep 22, 2008)

Be careful with the hockey pucks, especially if you've cut them. They split over time.


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## s2kvondeutschland (Mar 19, 2011)

invisiblewave said:


> Be careful with the hockey pucks, especially if you've cut them. They split over time.


Yep. Good thing they're cheap!

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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

phaetonjohn said:


> Sit rep.
> 
> Unable to locate the drain plugs for both the centre and front diffs.
> Unable to access the fill plug for the centre diff, and unable to remove fill plug for front diff.
> ...


For what it's worth: My center differential left seal is leaking and the mechanic at the dealer doesn't quote any costs for new fluid. He says they usually reuse the old fluid and top it off. 

-Eric


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## phaetonjohn (Oct 24, 2014)

53PL-50AAA-VW611BAN said:


> For what it's worth: My center differential left seal is leaking and the mechanic at the dealer doesn't quote any costs for new fluid. He says they usually reuse the old fluid and top it off.
> 
> -Eric


Sounds good to me!


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## Dangerrous (Sep 14, 2014)

The torsen drive requires a friction modifier to work in conjunction with the torque splines, the best way to see if the additive has broken down is wheel scrubbing when you're on full lock. The correct fluid is ridiculously expensive, personally I'd tap up TAZ for some additive to go with the diff oil. There's plenty of info regarding the torsen drive for VAG cars of this age. I used redline, it worked but I couldn't recommend it as I may revert to the WV/ZF stuff at a later date
Darren


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## phaetonjohn (Oct 24, 2014)

Dangerrous said:


> The torsen drive requires a friction modifier to work in conjunction with the torque splines, the best way to see if the additive has broken down is wheel scrubbing when you're on full lock. The correct fluid is ridiculously expensive, personally I'd tap up TAZ for some additive to go with the diff oil. There's plenty of info regarding the torsen drive for VAG cars of this age. I used redline, it worked but I couldn't recommend it as I may revert to the WV/ZF stuff at a later date
> Darren


Hey Darren,

My oil cost just under $27 a litre, and I only used a litre, so I think it's not too bad of a price.
It only rumbles during a full lock turn in second gear. Then again, it's done that for over 3 years.


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## Dangerrous (Sep 14, 2014)

mine scrubbed tyres on full lock, now it's fine. The redline was £20 for a litre. It just seemed thinner than the VW diff oil that I purchased; I was going to use this until I found out about the STURACO FM 1992. 
D


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## invisiblewave (Sep 22, 2008)

Wait! Darren & Taz are two different people??? Who knew?


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## _Taz_ (Jan 8, 2016)

Lol... I hope so.

Yes, just to add chaps the fm fluid you can get via a mb dealer in a 50ml vial ( I think ) or just buy a litre of the stuff, I got mine from simon at Bristol trans.... You should put this in the centre diff, as it uses the fluid as part of the lockup process.... But I it breaks down, the fluid that I, it locks up too early, hence the Quattro rumble at full lock which doesn't help the torsen diff internals! 

Cheers!


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## invisiblewave (Sep 22, 2008)

Kent/Essex, it's all the same to me!


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## hweeres (Dec 18, 2014)

*can you elaborate, please*



s2kvondeutschland said:


> There are no drain plugs for the front and center differential. I eventually used a syringe with nylon tubing.
> 
> I was able to use a hex key on the front. Or maybe I used a hex bit on a ratchet. The center was a pain. It involved a floor jack and removing the mount bracket.
> 
> ...


Hi,

what do you mean by using a syringe with nylon tubing? My front diffs are loosing oil as well and I'd like to top them back off.
Did you use the S2 fluids, or the A2?

Thanks!


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## invisiblewave (Sep 22, 2008)

I used something like this for filling the transmission. You can buy the tubing at Home Depot.


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## s2kvondeutschland (Mar 19, 2011)

I used the tool invisiblewave pointed out to fill the differentials.

I used Castrol Syntrax 75W-90 in my three differentials. 

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