Rear Diff and Gearbox Fluids

[ninjag]

Looking for some advice please for the S4 B8.5. I've done the dual clutch fluid and now looking to do the rear diff and gearbox inc. associated as preventative maintenance. I'm hitting 70k miles now.

Could anyone confirm that these are the correct fluids and volumes? I'm leaning towards just getting genuine fluids for the sake of saving something like £65 over Castrol/Motul etc and I'm wary about getting non-genuine for the gearbox as I'm sure the workshop manual mentions that the VW Genuine stuff has an additive in it for the transfer case.

- Rear Diff (regular not sports) is showing as requires G052145S2 which I believe is Synthetic 75w90 and requires 0.9 litre.
- Gearbox (including the transfer case and the front diff) is showing as requires G055532A2 which I believe is also Synthetic 75w90 and requires 4.5 litres

I think there are stretch bolts for the support frame (X-Brace) which require replacing as well?
- WHT005372 x2 & N91151101 x4

I've got a 500ml syringe for getting the fluids in. Does anyone know if this is all correct?


Thanks

 

[Dippy]

I had my sports diff done in 2020 and the invoice shows 1 x G052145S2 axle oil and 1 x G055515A2 rear diff ATF
I had my transmission done last month and the invoice shows 7 x G052529A2 s-tronic oil and 4.5 x G055532A2 transfer oil

 

[ninjag]

I had my sports diff done in 2020 and the invoice shows 1 x G052145S2 axle oil and 1 x G055515A2 rear diff ATF
I had my transmission done last month and the invoice shows 7 x G052529A2 s-tronic oil and 4.5 x G055532A2 transfer oil

Perfect thanks, looks like it all matches up (the non-sport diff part that is) and the gearbox.

I used about 5.8 litres when doing my DSG, which worried me a little at the time but I didn't do the internal filter, only the external. I'm guessing removing the sump and internal filter could push it into 6+ litres? I'll do the internal when it's due again.

Rear is starting to feel a little jarring, I think the rear lower track rods need changing but will check first. Will need to remember to mark the position of the bolts if I do change them.

 

[Dippy]

I'd have to check to be sure but I think mine was just a straight ATF & external filter service - I'd have to specifically ask for the sump work to be done. Although my car is now over 7 years old, it's still only done 23K miles and so I don't think there is any need yet. Have a check on Audizine as there seems to be quite a number of people there who do their own servicing. Certainly often 7 litres is quoted but IIRC I have seen comments of people having used less.

 

[ninjag]

I had my sports diff done in 2020 and the invoice shows 1 x G052145S2 axle oil and 1 x G055515A2 rear diff ATF
I had my transmission done last month and the invoice shows 7 x G052529A2 s-tronic oil and 4.5 x G055532A2 transfer oil

Could I ask if they replaced the stretch bolts on yours? I've just picked up the rear diff fluid from Audi today but they only had 1 litre of the gear oil in stock because they never change it; usual seal for life comment and he admitted that they consider 100,000 miles as the lifespan.

I then went to get replacement stretch bolts and instead of what I spec'd above, he said there were actually eight required? He showed me the diagram (which was more detailed than the audi.7zap one, so I went for it. But when I look at this one it's not so clear: https://audi.7zap.com/en/rdw/audi+a4+s4+avant+quattro/a4q/2015-736/3/399-399075/#13

There is that Part 13 in brackets which appears to be another set of Part 15 (triple square) but it's strange to not just say x4 of part 15 instead?

 

[s4chopper]

Could I ask if they replaced the stretch bolts on yours? I've just picked up the rear diff fluid from Audi today but they only had 1 litre of the gear oil in stock because they never change it; usual seal for life comment and he admitted that they consider 100,000 miles as the lifespan.

I then went to get replacement stretch bolts and instead of what I spec'd above, he said there were actually eight required? He showed me the diagram (which was more detailed than the audi.7zap one, so I went for it. But when I look at this one it's not so clear: https://audi.7zap.com/en/rdw/audi+a4+s4+avant+quattro/a4q/2015-736/3/399-399075/#13

There is that Part 13 in brackets which appears to be another set of Part 15 (triple square) but it's strange to not just say x4 of part 15 instead?

2 x Bolts closest to the engine on X Brace are different to rear Bolts. Re-use old bolts at least once, completely fine for X Brace.

Sometimes Audi spare parts quote full quantity of same bolt for a specific area or complete car.

 

[ninjag]

Ah damn, I've just realised that I don't even need the x-brace bolts as I'm not dropping the transmission oil sump. It's the gear oil I'm doing, so it's the cross member support bracket I'm removing (will obviously be supporting the transmission). I can't find torque specs for the bolts and nut though.

Oh well, I guess all is not lost as I'll be replacing the internal filter/strainer and transmission oil sump when I do my next DSG fluid change so I'll need the bolts for then.

 

[ninjag]

70k miles and the rear diff fluid wasn't too bad, however, the transmission gear oil didn't look as good. It didn't stink of being done unlike my ZF fluid.

I reckon it would have been fine for a little longer, but it's such as easy job so why not.