SchwarzY2kS4

B5 S4...just changed the front drive axles as well as a complete control arm kit. Literally the day after, I noticed a sizable puddle of red fluid on the garage floor. Passenger side drive axle where it meets the flange is really wet. It appears I stressed something there too much while changing the axle and control arms. I immediately figured I stressed the output flange seal. I had my independent Audi mechanic/buddy order me a seal 01V 409 399. When I picked it up he said that the leaking fluid is typically a yellowish color and not red, and said that maybe someone put Redline fluid in it, which I doubt is the case because prior to my ownership of this car was maintained at an Audi dealership. Without tearing it apart, I am now wondering if I have the wrong seal. Thoughts?

AudiAllTheWay

Suggest to inspect your motor mounts from underneath vehicle. Stock mounts are red fluid filled and when the rubber mount starts to tear and fail the red fluid will leak out of a small drain hole in the metal bottom of the mount base. Replacing motor mounts on a B5 S4 is a PITA but there is a trick, if your willing to support the engine from above and remove the mount to block brackets with long hex extension. Saved me hours of work.