I've been getting a whining noise when driving in 5th and 6th gear at lower RPM's? When I pull my foot out of the gas the noise goes away??? It seems it happens above 50 MPH, I can't tell if its the motor or it almost sounds like it is coming from the rear end of the car? I am absolutely clueless on this? Anyone have any ideas?

I'm not sure, not much to go on...but you don't feel any vibration do you? That rules out suspension and driveshaft at least. If you do over 50 in fourth gear do you hear it?

What about road conditions? Does it change on different road types? That would rule out tire issues.

The only thing that comes to mind is the throwout bearing in the tranny, but I'm not sure how you'd even go about testing it. I'm not sure if it would start making noise if it was wearing at higher speeds. It shouldn't....but????

I can't say for sure what you are experiencing, but I know when I'm lugging the motor a little (5th or 6th between 40-60 mph) I hear a little more gear whine than usual.

Do you have an auto?? If so did you do any mods to the car at all? Just trying to get the full scope on the situation!!

You are most likely having a problem with gear noise from the rear. It could be that the gears are worn or possibly that a bearing inside the rear is going bad. Mine also does this a little but then again I'm pounding on it at the drag strip too. Try changing the fluid in the rear and check for metal filings in the fluid.

I have the car scheduled to go in tomorrow for service, be glad to see what this was caused from. Their checking this and full tune up and fluids checked and changed! :)