I've got a 2000 A4 Avant Tiptronic. After it shifts into second gear, there's a bumping under the center console area every time, otherwise it drives smoothly. This happens only in 2nd at a certain rpm. It feels just like I drove over a set of small speed ripples/bumps.

I'm wondering if this is related to the drive shaft. Any ideas would be appreciated. Thanks.

 

Center shaft carrier bearing would be a good place to start looking. You'll need to remove the heat shield to take a look. 4 little nuts and then work it down. Single exhaust on the 1.8l makes it easy to inspect. Otherwise you may have to drop some pipes. Grab ahold of the center shaft near the center support, carrier bearing, and see how much play you have. You should be able to tell by how much you can move the shaft. You may even be able to reproduce the noise. Strange it only happens in a certain gear but when mine went it wasn't a constant thumping.

 

Thank you. I think I'll put it up in the air this weekend and take a look.

 

Mine was exactly like that on my dear departed 96. It was deceleration at a certain speed....20-28 mph. Was one of the cv joints on my drive shaft.

 

Interesting. I will look at cv too.

 

There is a CV joint at each end of the center shaft plus the center support bearing. If you can move the center shaft at either end or in the middle you should be able to make the sound or at least feel it. This whole thing may be a tad over engineered.