Rear differential oil leak - needs replacement

[rav6370]

All Took the car in today as I was hearing a slight hum/whine at cruising speeds, 1500 to 2000 RPMs. The dealer had to compare the noise to another s4 of the same year to see if it was a normal noise. Turns out that that rear diffential was leaking and that's were the noise was coming from. The oil was dark with metallic flakes so they ordered the part today. Should have e car back by Saturday. They have had a 2011 s4 with a similar problem in the past but that's it. Anyone know of this to be a common issue on the b8s? Or just a random fluke? Thanks for the input...

[jdgamble]

Very common. Several threads about it.

[FatalBert]

Originally Posted by rav6370

All

Took the car in today as I was hearing a slight hum/whine at cruising speeds, 1500 to 2000 RPMs. The dealer had to compare the noise to another s4 of the same year to see if it was a normal noise. Turns out that that rear diffential was leaking and that's were the noise was coming from. The oil was dark with metallic flakes so they ordered the part today. Should have e car back by Saturday. They have had a 2011 s4 with a similar problem in the past but that's it.

Anyone know of this to be a common issue on the b8s? Or just a random fluke?

Thanks for the input...

No the differential leaking is not a common problem at all. The common issue on the 2011's is a CV joint leaking oil, not the sport diff. This would not cause a whining noise that you were hearing and has no "metallic flakes". So your issue does not sound common.

[jdgamble]

Originally Posted by FatalBert

No the differential leaking is not a common problem at all. The common issue on the 2011's is a CV joint leaking oil, not the sport diff. This would not cause a whining noise that you were hearing and has no "metallic flakes". So your issue does not sound common.

You sure about that?

http://www.audizine.com/forum/showth...ferential+leak

[FatalBert]

Originally Posted by jdgamble

You sure about that?

http://www.audizine.com/forum/showth...ferential+leak

Yes, see post 363 in your link:

http://www.audizine.com/forum/showth...=1#post7487360

If you need more proof see the TSB itself:

"Insufficient sealant on the protective
cap of the inboard constant velocity
joint can allow oil to leak passed the
protective cap or bolt holes. It may
appear like a sports differential side
seal is leaking.
Figure 1.Structure of drive shaft on differential
side.
( 1= protective cap) (3 = inner constant velocity
joint)
All greases consist of oil and
thickener. It is a normal characteristic
of all greases that some oil may
separate from the thickener. Due to
the oil’s lower viscosity, only the oil
leaks from the axle and this can make
it appear like the sports differential is
leaking"

[jdgamble]

Interesting... I learned something new today!

So OP... They are replacing the whole diff?

[mark_nimda]

Originally Posted by FatalBert

No the differential leaking is not a common problem at all. The common issue on the 2011's is a CV joint leaking oil, not the sport diff. This would not cause a whining noise that you were hearing and has no "metallic flakes". So your issue does not sound common.

this. (The key word here is "noise".) I had my new seals put on 3 weeks ago and since then, no fluid from the seals.

[rav6370]

Originally Posted by jdgamble

Interesting... I learned something new today!

So OP... They are replacing the whole diff?

Yes they are replacing the whole Diff, part will take 3 days or so and less than a day of actual labor.

Mark - did you have a differential issue or was yours related to the TSB for the joints? Did you have a noise before the problem was fixed?