In Reply to: Whining at 78mph posted by Patrick O. on January 29, 2000 at 00:23:55:
I have the same issue on my '97 540ia. At approx. 2300RPM the whine is the most apparent. It dies down drastically on either side of this RPM. Infact, the car runs smooth as silk above 80MPH or below 74MPH. The level of noise is also not consistent, some days it is more apparent than others. (I can also feel a slight vibration in the gear stick at this RPM)
I think it is some sort of resonance noise. I have taken it to dealer twice, but both times the whine was negligible, and they could not trace the problem.
Let me know if you get any answers from your dealer.