When I back up the my e53 (while turning) I am getting a squeel sometimes. I thought it might be the power steering pump but I know when I had that go on my e46 it made a low growling sound when I turned it either way. Maybe something else in the suspension?

I had some issues with the transmission (backup solenoid) which I believe I solved when I replaced the TCC solenoid although my wife who drives the car all the time doesn't have that faith and is convinced that the squeel is transmission related. I don't believe that it is as it sounds like it comes from the front of the car.

Any thoughts??