[Wyle_E]

I just discovered the first mechanical problem with our new '99.5 A4. The passenger side rear differential axle seal appears to have failed and is causing a drip on the garage floor. Looks like about one drip per day, but I don't know how long it's been leaking.

The past receipts show the same seal was replaced under warranty 2 years ago for the previous owner, so I'm wondering if something else is causing the seal to fail. Any ideas? Bad bearing maybe? How much would that cost to fix?

Thanks.

 

[cheesemax]

I had my A4 on a lift a while ago and noticed some gear oil around the rear diff to the point where there was a bead hanging from the surface of the diff. No drips on the floor that I ever noticed. Asked the dealer about it and they promised me that the diff on a quattro will "sweat" the oil in this fashion and it is 100% normal.

 

[Wyle_E]

Seepage is certainly inevitable when you have an oily axle spinning around inside a rubber doughnut. Something on mine has definitely failed, as there's oil splattered all over the side of the gas tank AND dripping on the floor. It could also be the drive shaft seal, so I have to get under it to be sure.

Has anyone done either of these seals? Is one more difficult than the other? Does anyone have a Bentley manual that might shed some light? I'm about to order one on-line.