Scraping/Grinding noise when rolling along at idle speed

[rjr1959]

Hello All,
Proud owner of a cherry (almost) 2000 Z3 Roadster, 80k miles. I'm pretty much a shade-tree mechanic - I can do a lot of things, but if it came to say, rebuilding an engine, I'd go to a pro, mainly because I don't have tools, time, patience. Anyhow, here is my issue.

If I drive down the road at idle speed, or just above it, I hear a scraping/grinding noise that sounds like some kind of bearing gone bad to my noobish ears. The car is an automatic (sadly). If I continue rolling along, and put the tranny in neutral, the noise stops. The noise is present in all other gears, including reverse. The noise sounds like its coming from directly below my butt, or a little further back.

Car drives and shifts just fine. That noise is annoying me though. Any ideas where I might look. Hopefully I've described it enough for one of the experts to give me some ideas.

Thanks
Robert

[Vintage42]

Could be the flexible coupling (giubo), the bearing in the center of the drive shaft (CSB), or the universal joint. For a look at them...
http://www.bimmerforums.com/forum/sh...sc-(Guibo)-DIY
http://www.pelicanparts.com/bmw/tech.../E36-Guibo.htm
http://www.pelicanparts.com/bmw/tech...ft_Bearing.htm
https://www.bimmerforums.com/forum/s...2#post24844412

[PbFut]

Given the driveshaft continues to rotate 100% of the time while moving and the noise stops when car is in neutral and happens while in all gears, your problem is very likely within the tranny. My guess is the torque converter. And it is truly a guess. Good luck. Please report back finding. Curious as to result.

[rjr1959]

Given the driveshaft continues to rotate 100% of the time while moving and the noise stops when car is in neutral and happens while in all gears, your problem is very likely within the tranny. My guess is the torque converter. And it is truly a guess. Good luck. Please report back finding. Curious as to result.

Will do. I'm going to put it on a rack this weekend and see what I can see/hear. Thanks to both of you for the suggestions.

[Jewel53935]

Did you identify the source of the problem? I have a similar noise. Thanks