So I've had a 2002 Cavalier for a couple weeks now. Changed the oil, the ATF looks ok, coolant needs a change, brake fluid looks ok, PS fluid could use a change but isn't horrible. I've noticed once the car is at operating temperature there is an audible whine. It isn't terrible loud but it is noticeable. The pitch varies with the engine speed, but only while in drive. I've put it in neutral and park and revved it and the whine doesn't occur then. I've shifted to neutral while going down hills and the whine 'spools down' as the engine drops to idle speed. I haven't tried revving it while rolling in neutral. I was thinking maybe water pump but I would think it wouldn't matter if it was in gear or not. Any ideas? It drives and shifts fine.