Hi all,

I have a 1998 2.8 Avant Quattro automatic. I recently replaced the front passenger wheel bearing, and now I can feel a vibration in the seat when I give it gas between 20-40mph.

It doesn't vibrate when I coast or rev the engine in neutral, it only vibrates under load. It seems to be more noticeable going uphill or with more people in the car. I put on a different set of wheels, and it doesn't go away, so I know it's not an unbalanced wheel problem.

I thought it was the axle was bad, so I tired putting in a used oem axle, and then a new aftermarket axle, but neither made any difference.

I was pretty sure the vibration was from the front passenger side, since that's the side I did the bearing work on. But now I'm having doubts as to where the vibration is coming from. I also replaced the outter tie rod ends and upper control arms not too long ago.

Could it possibly be the front differential? I found a lot of play when I rotate the hub by hand with the opposite wheel on the ground. I'm not sure if this was normal. Can anyone confirm? Here's a video:

http://www.youtube.com/watch?v=QOa0LafAONA

I'd appreciate it if anyone had any ideas as to what else might be causing this vibration. It's pretty embarrassing when I have friends riding and it feels like it's going to fall apart :P

 

engine mounts?

 

it could be your hub... have someone else drive ur car and u can listen with clear mind

if at all possible get it on a lift!

 

hmmm i have the same problem on my 02 avant. i actually just posted almost the same thing, different key words or else i would have seen this one when i did a few searches. tomorrow i am taking my car to the dealer and when i find out what they say i will let everyone know. i just had the tb replaced at the dealer and now my car does the going up hill vibrate/shutter thing. dealer told me my cv boot was torn and needed to replace the axle, i said no thanks can do it myself and now my car feels like the wheels are about to fall off. hmm

 

to be honest after watching the vid it looks like it could be a problem with the hub ....

 

I haven't inspected the engine mounts. If engine mounts were the problem, wouldn't it also vibrate when revving the engine while parked?

The hub could be it. The vibration did start only after I installed new bearings. But I'm pretty sure I pressed them in correctly and they were smooth when rolled by hand after install. The hub is less noisy now with the new bearing than with the old one. So I assumed the bearing/hub was ok and something else (like the axle) got screwed up in the process of doing the bearings. I haven't really heard of a case where vibration came from bad bearings, but I will definitely check it out when I have the time to take the whole upright out.

If you look closely at the video, the looseness comes from within the differential I think. The connection from hub, to bearing, to outter cv, to inner cv is solid. They all move as a unit.

I also did my timing belt, but that was many months before this vibration started. I think if they messed up on the T-belt change, and it was off a tooth or something, your car would be running WAY worse than just some vibration under load.

From what I've read in forums, it seems like a bad axles (especially at the inner cv joint) are what cause these vibrations most of the time. If you had a torn boot for a while, there's a good chance that cv joint had started to wear, and then jacking the car up and down a few times during the T-belt change aggravated the cv joint enough that it started to vibrate.

Let me know what the dealer says. I think the axle is your problem. But then again, I also thought the axle was my problem, and I went through two of them without any luck.

 

your hub is fine. Differential is also probably ok too. That much play is normal.

 

Well, turns out it was my right side inner cv boot that was causing that same problem. dealer replaced the whole axle for $360 tax included. They used an aftermarket.. I think they got it from napa.

 

Thanks for the replies guys. Glad to hear your new axle solved the problem.

I got my car on a lift, and the vibration is a lot less noticeable. Like I mentioned before, you really feel it when the car has more people in it. On a lift, with a the weight off, the vibration is kinda still there, but not enough to pinpoint where it's coming from.

I'm thinking of maybe replacing the axle on the opposite side now. Kinda running out of ideas.

 

hub beerings ....