98 z3 convertable

98 Z3 convertable with a bad vibration only at 70 and above. Vibration is only apparent when looking into the rear view mirror and seat. Steering wheel is smooth. Wheels have been balanced twice and a front end alignment @ a BMW shop. Also new KYB shocks front and rear. Wheels are aftermarket.

Any thoughts?

Clif

Clif, how quiet is it in the car? I mean do you hear a rumbling or something that sounds like to much tire noise? I thought mine was tires, then I started getting a ratcheting sound at certain times when I got into the gas. Come to find out it was the u-joint in the driveshaft right behind the carrier bearing. Once changed, the car was super quiet and rolled a lot smoother, no vibrations, etc. Just thought I'd share "just in case". Good luck.

SMAY964,

I am also hearing a noise at higher speeds (with the cooler weather,now noticeable with the top up). I thought that it was the diff, but I do not get the normal change of sound when going around corners indicating a problem, so you got me thinking that it could be the U joint. I was planning on the changing the diff oil before winter so I will look at the U joint while the car is up on the jack stands.


Al
98 Z3, 2.8L, 43K miles

loose mirror.

Not sure what you mean. The whole mirror assembly, or just the glass? I doubt that this is the problem as the noise seems to be coming from behind me. BTW - There is no vibration, just noise.


Al

My car has always (at least for the last 5 years) made a whirring sound on deceleration. I'm sure it's something to do with the driveline, but it's not bad enough to warrant changing anything yet.