Audi A6 C7 2012 3.0tdi Quattro differential oil specs and quantity advice please?

[aw911]

Hi

I'm new to the A6 C7 platform and have just purchased a 2012 A6 Avant 3.0tdi Quattro with the S-tronic gearbox (I believe the gearbox variant is 0B5). The engine code is CDUC with transmission/gearbox codes of MNB/NPB on the vehicle data sticker.

I have carried out a full service....6.4 litres 5w30 fully synthetic engine oil, new G12+coolant, fuel, oil, air and pollen filters and just had the S-tronic ATF fluid and filter renewed by Audi (via their £225 fixed price service)

I am specifically looking for info on the front and rear differential oil specs and quantities required. I understand that they are 'fill to spill' and when the car is completely level...but I would like to have a rough estimate of how much I require.

I believe that the spec is 75w90 gear oil GL5 and that the rear differential hold 0.9 litres.....but I'm hoping to find some further info on both the front and rear differential The audi opinion on the differential etc....is that they are 'sealed for life'....yet the s-tronic ATF fluid is renewed every 36k despite that supposedly being 'sealed for life'.

My previous Audi was a 2007 A6 C6 3.0tdi quattro 6 speed manual and I changed the gearbox and rear differential oil at 80k intervals....that vehicle has now done 236,000 miles and they were also supposed to be 'sealed for life'...however when I took ownership at 140k miles the gear oil was pretty dark and murky....my last change at 220k miles the fluid was still clear so I think there is benefit in doing this preventative maintenance.

The only place I can find any real info is on the USA audi forums and they have different platforms to us engine wise....so i am hoping that a UK owner has maybe done this on their S-tronic MTF fluid (not the ATF fluid) and rear differential oil and can shed some light. Or perhaps someone who has access to official Audi data on specs and quantities of these items.

I'm guessing because Audi state that it is sealed for life that is why nothing exists officially in Audi documentation that I can find while searching via the internet.

Also does anyone have part numbers for the S-line gearbox and engine undertray as I can only find part numbers for the standard model and apparently these aren't compatible with A6 S-line and S6?? The dealer quoted an eye-watering £479 for both and did not divulge part numbers in the quotation so I could not do any further research on this.

Any help or advice would be gratefully appreciated as I am hoping to get this wrapped up next week while the car is up on axle stands as the wheels and brake calipers are currently away being refurbed.

Many thanks

[Alan02]

I dont know why Audi dont do the MTF at a gearbox service. I had mine done at a gearbox specialist and had all oils and filter, plus the center diff re-sealed as it had a minor leak for just over £300.
Get the MTF oil changed even though it is stated as `Lifetime use`, and yes, there is a fill/level plug and that oil does the center and front diff.

[aw911]

Hi

Thanks for the reply. I've done loads more research overnight and found an amazing write up from a guy who has done the full service on the Audi with the same s-tronic box but the sports differential at the rear differential.....however it's the front MTF that I'm primarily interested in. He lists all the specs and quantities....link is below...I hope it doesn't break any forum rules.

RS5 full fluids service how to (transmission and rear differential) (https://www.audizine.com/forum/showthread.php/833033-RS5-full-fluids-service-how-to-(transmission-and-rear-differential)

The main issue is the MTF fluid....there is no info about it whatsoever. The spec is 4.5 litres of VAG G 055 532 A2. However, there is no info about the specification of this oil anywhere. It is pretty expensive to buy online if you can find it anywhere....roughly £20 a bottle for 1litre. I'm going to call VW parts dept shortly to try and get a price for 5 litres (as they will be cheaper than Audi from experience....for the same item).

Going on the Millers Oils website.....they specify a 75W80 gear oil for the manual transmission fluid in this box so I have emailed their technical department with the VAG part number to see what they say.

I can get 5 litres of Millers TRX 75W80 fully synthetic gear oil for £30. The rear differential is 0.9 litres 75w90 spec which I already have from other vehicles.

Hopefully Millers Oils will get back to me with a definitive answer regarding equivalent oil spec and then I can update in case anyone else decides to carry out a DIY fluid change in the future.