Differential Oil Change

B6/7 S4/RS4
#1

Hi all,

I will be getting some maintenance stuff done on the car soon.

My car is a 05.5 S4 with automatic tranny. It currently has about 53k miles on it.

The car has always been city driven with some spirited drives up the mountain from time to time during my ownership. Does car need a rear diff oil change?

From what I have gathered, and please correct me if I am wrong, the rear diff does not see as much stress as the front diff. Thus, a lot of times the rear diff oil doesn’t even get changed at all. But I am not saying I am not going to change it, just making sure I am not doing this too early.

This brings up another question, what about the front diffs? I saw plenty of rear diff oil changes DIYs, but saw none for the front diff.

Thanks in advance, cheers!

#2

There is no front diff. It’s part of the transmission and it gets lubricated by the transmission’s ATF. That said, if you are at 53k you are definitely due for an ATF change. Justincredible has the DIY posted somewhere, either here or Audizoo. A pan drop should be sufficient I think. Change the filter and refill, then maybe do that every couple years

Rear diff fluid should be done every few years, but it take under 2L of fluid so it won’t hurt to do it more often, and it’s easy. Use Motul Gear 300.

#3

Thanks for your reply Joe. I think I just made a fool out of myself for asking about non-existent front diffs lol

Yup, I saw Justin’s DIY on Audizoo(lol) and ordered the parts from JHM. Seems like a pretty straight forward maintenance. I believe this is probably the first ATF change for the car since it left the factory. Motul Gear 300 is also the oil my shop recommends. Based on googling, it seems like this oil has a lot of positive responses.

#4

Yeah it’s by far the top choice amongst s4 guys. OEM fluid is very good too though