Both of m turbo s wheels made a high pitched screeching sound if I run it with really high FFB. It only does it in GT5 if I have the in game FFB at 10 and the wheels FFB turned up to I think 7 or higher.
its the FF motor. Its indicating, that its operating at maximum (which is fine&save) this noise happens (and can not be prevented according to Fanatec Tech support) when you have FF on 100 and 900 degree steering.
Set the steering degr. to 270 and the noise will be gone.
I was a bit concerned also when i noticed it first, but there is no way of getting rid of it unless you exchange the FF motor (which is strong enough).
You need to either change the degree or turn up the volume of your stereo...