The noise no one can find!

The second of my two perplexing problems with my 1990 735iL: the noise no one can find. This is one of those "every once in a while" noises. Here is the scenario: usually from a dead stop...as I begin moving there seems to be a sound much like the one the playing card in your bike spokes used to make when you were a kid. It sounds like it's in the right front. It increases/decreases with the speed of the car...nothing to do wioth increased/decreased RPM of engine. No change when the transmission shifts. SOmetimes it last 15 seconds, other times a couple mjinutes...but it always goes away after a short period of driving. Two different mechanics have looked for loose "things"...but, of course, the sounds never happens for them. Any suggestions would be appreciated. Thanks.

Had that same noise on a '92 735iL -- intermittent, but usually after sitting, idling a while in park, and then going back into drive. If it persisted more than a few seconds, I restarted the car, and it always cleared up, leading a few of us to believe that it was ignition related -- probably a wire heading south... Never got a chance to resolve it, though.

I had a similar problem on my '92 E32 and it turned out to be that the differential was locked. Replaced with a rebuilt diff and the noise was gone.

Same thing happens to my 1990 735iL. Scares the hell out of me every time.

Norm,
The post on diff made me think of my '88 E32 whihc started making a very odd noise from stop and in slow turns that I called a grinding noise. Sounded like gears to me but could sound liek a card on spokes to others?

Turns out that BMW non slip diffs require specific oil compared to the non-slip dif. If you have ahd the rear end lubrication oil changeds they may have used the wrong type and this caused mine to make an awful noise until I had ti drained and filled twice to flush it out with the porpre stuff.