I recently noticed a moderate whine while driving my 2001 Chevy Impala (100k miles) on the highway. I thought it was an engine bearing until I realized that it changed in pitch and volume as power changed, but not rpm per se. That is, as I accelerated or went up a hill, it got more pronounced, but went away when coasting, even if I put it in nuetral and revved it. Also, I discovered that if I put the shift column in '3' (forcing it into 3rd -- it is a 4 spd tranny, right?), it never whined?
<br/> So I'm concluding that it is the transmission, but I have no idea what the problem is, or what I can do about it. The tranny fluid is full, but I've never changed it or the filter. I'll start there, but need help to really figure this out.
<br/> What do you think