S4 SOM

While cruising, when +4k RPM I can hear a noise (and feel vibration) that I didn't have before the new 4:1 torsen being installed.

Also when I go from 3rd gear->2nd gear I can feel a vibration (I can feel it on my butt) no vibration felt on steering wheel. My mechanic who did the install said that he carefully marked the prop shaft (his words). Still the obvious thing that I think is misaligned prop shaft.

Well is it possible I have a bad 4:1 torsen? I would think Stasis has a very good QC on their manufactured parts.

I talked to my mechanic and I'll bring the car tomorrow am so he can see (hear and feel) what I'm talked about. I will bring my original torsen diff in case he wants to switch it back for diagnosis purpose.

What else should he look at? I don't want to drive the car today, I'm afraid I can break something (e.g. bearings)

Mike@StartupRacing

It might not have been preloaded properly.

SilverA4Fun

consistent vibration all RPMs...my guess is drive or input shafts, but more likely drive based on rpms. Mine stasis center diff has been problem free for 2months

nyet

i would guess input shaft or clutch related

wagongotya

Hey Rejean, the propshaft has a guide that's located at the center u-joint. If it's not aligned properly you will get a vibration in the propshaft. Here's a picture of what i'm talking about

<img src="http://mnaudi.com/mymnaudi/images/1216/IMG_3206.jpg">


Check it out, good luck<ul><li><a href="https://forums.audiworld.com/s4/msgs/2559716.phtml">more info</a></li></ul>

Don@STaSIS

as you expect to see a vibration with the propshaft misaligned at certain road speeds. The Torsen would be unable to produce a vibration at certain rpm's. Not sure what the issue could be, check the propshaft just to be certain.

Cheers,