Please forgive me if I'm starting a redundant thread, but I've searched high and low for this particular issue and haven't found a thread where someone was experiencing the same exact symptoms. BTW, I have a 2004 A6 3.0 Quattro Avant with 84K.

Symptoms:

-Steering wheel vibrates when driving over 70mph, does not disappear even when I hit 90mph, gets a little worse actually. I can feel it slightly at lower speeds (35-40mph), but not as bad.

-Along with the steering wheel, I can feel vibrations under my driver's seat, and I could also feel them slightly when I was riding in the passenger seat

-I can also see the visors shaking, so basically something is rattling my car above 70 mph

Recent Fixes:

-Replaced all 8 control arms, front struts, and strut mounts within past month

-Tires are Fuzions that were put on back in April/May, don't appear to have too much uneven wear from riding on busted struts/control arms.

-All four wheels were aligned and balanced last week

Despite all of these things, the problem still persists

Possibly Related:

-Passenger side engine mount is leaking purple goo

-Transmission clunks pretty noticeably when shifting from Reverse to Drive. I can hear it and feel it when pulling into my garage. Of note, I have not changed the tranny fluid/gasket yet so this may be completely unrelated to the vibration. However, could a worn transmission mount be causing the clunk and the vibration?

If anyone has insight, or if this has been addressed already I would appreciate the help.

Thanks!

 

Could possibly be engine mounts.

Perhaps bent rims?

 

From my recent experience tranny problems usually show more at low speeds. If it was a bent rim they should have found it in during the alignment. To me it sounds like it could be the rack and pinion. If you crawl under the front end of your car u will see a piston looking thing that has a boot on each end the cv axles run out of those boots to the wheels. When a rack and pinion goes it will normally leak power steering fluid from the boots that cover your inner tie rod ends. I hope this helps man.

 

BTW try to gently move those boots around. With 84,000 miles chances are they are ripped anyway you will get a steady stream of power steering fluid out of the rips if you move them around.

 

a4 b5 fwd 1.8t. Vibration at 60+ MPH.You may have figured out my issue too. I have another question. I was planning on replacing the tie rod inner and outer which requires me to replace the steering rack boots anyways right? Do I need to replace the steering rack or just the boots and the tie-rods (in my case)?

 

Thanks. I will take a look and let you know what I find. Unfortunately, I'm having other issues at the moment. EPC light came on and is causing engine to idle high and rpms to fluctuate while driving. Once I get that figured out, I'll be back on the vibration issue.

 

Well, I'm finally getting back to figuring this out. Since my last post I replaced the front driver's side axle (outer cv joint was shot, and mechanic said he could only order full axle). I also had both top engine mounts, snub mount, and tranny mounts replaced since they were showing signs of wear. Finally, I fixed two bent rims. Nevertheless, the vibrations are still there!

So my entire front suspension is new (minus passenger side cv joints, which are fine), rims are straight and all major engine/tranny mounts have been replaced, but those vibrations are still there. I'm out of ideas...any help?

 

Not sure if you figured out your problem, but have you checked your driveshaft. I had the same issue with my '00 4.2 and had the driveshaft replaced.

Just my humble opinion. Good luck!!

 

Normally when a vibration is felt in your seat that is a tell-tale sign that something on the rear isn't right. Have you checked to see if your rear differential is showing signs of leaking from either the output or the input?

 

maeghyn: Unfortunately, I still have not fixed this problem. Other issues (replacing engine) have put this one on the backburner. However, the mechanic who replaced my engine said it sounds like it could be the driveshaft center support bearing although he said this vibration would be felt more in the console (directly above the driveshaft) rather than under the seat. He priced that repair at around $450 after parts and labor.

This makes me wonder if Nebuchadnezzar might be on to something with the rear differential. As soon as my bank account allows me to, I will be bringing it back in to have the rear differential looked at. Makes sense considering the rear differential has never been serviced and I have about 93k on it.

Once I figure this out I'll update you guys. Thanks!