B8.5 S4 Sport Differential Service Requirements?

[raceshop147]

Does anyone know if / when (mileage interval) the sport differential should have fluid exchanged ?

What type of oil does it take ?


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[LowKeyLoki]

It takes ATF fluid and the actual diff uses gear oil. FCP euro has a kit with both OEM fluids and drain/fill bolts. Idk what the service interval is, probably isn’t one but I recommend every 50k miles. The DIY thread for the transmission fluid covers the rear diff service.

https://www.audizine.com/forum/showthread.php/743933-B8-S4-Complete-DSG-Maintenance-Service-amp-Sport-Differential-Service-DIY

[raceshop147]

Thanks

I read for the 6MT transmission it is “lifetime” fluid

But the sport diff should be addressed every 100k

Appreciate the link


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[Smac770]

The type 0BF sport diff is "lifetime" fill for the rear diff gear oil as well as the clutch pack ATF for A and S models. For the RS models, it's replace the gear oil and the ATF at 35k and then every 40k. But if your RS never saw a track, or your S sees a track from time to time, then I'd go with the other's maintenance schedule.

If you have a 6MT, yes, "lifetime" fill for the MTF. Just check for leaks and top off fluid level if need be. The front diff and center diff are bathed in that same MTF for the 6MT.

Nothing wrong with doing any of the fluids however often you want, as long as it's not less often than any given service interval.

[bass_lover1]

I wouldn't treat any fluid as "lifetime" personally. Heck, you're even supposed to swap out engine coolant IIRC every 10-12 years, assuming of course it stays sealed and you don't have to replace a pump or thermostat...

I did the sport diff and mtf side of my dct at 99k miles. If I have the car at 150k I'll do them again at that time too.

[Corydms7]

I did the rear diff fluids (sport diff and the actual diff gear side as well) at 60k miles and it was still pretty clean. Probably could’ve waited longer, but wasn’t a bad idea. The front diff/center diff/DSG gear oil section (the same part as a 6MT) I changed out around 70-75k miles and it wasn’t horrible, but it was definitely a darker golden color. Overall gear engagement/smoothness/shifting quality didn’t get crisper from that though. I was at almost 75k though to.

[Corydms7]

Shift quality DID get crisper. My phone auto corrects lol. Was worth changing. I did the Redline MT-90 75w-90 GL-4 spec fluid for the center diff or DSG gear oil.

[3.0ss]

https://www.fcpeuro.com/products/audi-rear-differential-service-kit-genuine-audi-vw-g052145s2kt

[bass_lover1]

Shift quality DID get crisper. My phone auto corrects lol. Was worth changing. I did the Redline MT-90 75w-90 GL-4 spec fluid for the center diff or DSG gear oil.

I did all of mine at 99k and they all looked pretty normal, not much smell or dirty looking. First gear when cold definitely smoothed out. It used to stick and lurch into 2nd (my 2018 gti with 25k miles did that too), it still sticks but doesn’t lurch now. I chalk the stickiness up to a dsg quirk when below 40* outside. I plan on taking it to a few autocross events when it warms up so I’m glad that I did them now at least, one less thing for the spring.

[Corydms7]

I mean it wasn’t horrible, but it was a darker golden color. Definitely was starting to age. Yeah it just engages smoother and quicker and less notchy.



I did all of mine at 99k and they all looked pretty normal, not much smell or dirty looking. First gear when cold definitely smoothed out. It used to stick and lurch into 2nd (my 2018 gti with 25k miles did that too), it still sticks but doesn’t lurch now. I chalk the stickiness up to a dsg quirk when below 40* outside. I plan on taking it to a few autocross events when it warms up so I’m glad that I did them now at least, one less thing for the spring.

[bass_lover1]

Yep same. Surprisingly clean for the mileage, but definitely looked worse than the new stuff. When I did the mtf fluid on my 5mt Passat years ago, also about 100k miles, that stuff was nasty. Dark and stinky, like gear oil. I was expecting similar here, but didn’t experience that.

[rsfpc05]

Thanks

I read for the 6MT transmission it is “lifetime” fluid

But the sport diff should be addressed every 100k

Appreciate the link


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Not sure where you saw 100k for the sport diff. I think I saw 75k and did my at 70k

[raceshop147]

Any reason why the dealership says they don’t need to be changed ?

I keep asking about it and they say it’s not a requirement and not to worry …which makes me worry LOL

I live in CT, not sure if a reputable place where I could have this service completed - thanks all for the info and replies, much appreciated


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[rsfpc05]

I had Excelerate in Branford do my diff service last December when they were doing my DSG service

[LowKeyLoki]

Any reason why the dealership says they don’t need to be changed ?

I keep asking about it and they say it’s not a requirement and not to worry …which makes me worry LOL

I live in CT, not sure if a reputable place where I could have this service completed - thanks all for the info and replies, much appreciated


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The dealer would rather it break and sell you a new diff [:D]

[Smac770]

"Any reason why the dealership says they don’t need to be changed?"

Because that's exactly what Audi Corporate says is the maintenance schedule for the sport diff on the A and S models, "lifetime fill", no service interval. Only on the RS models does it get a service interval (35k and then every 40k, for the ATF and the gear oil). This should not be a surprise, it's right in Audi's maintenance schedule documentation. The RS model gets a change schedule because it's expected to see track time, unlike the expectation for the A and S models. If you take your S model to track purposes regularly, then you should probably go with the RS schedule.