I was told it was a carrier bearing, but that wouldn't make noise some of the time, and travel to the front end.

It was put on a lift today, and the noise was not reproduced.

When I am at highway speeds, throw it in neutral, and turn the car off, it still produces the noise. I've also been told ...

I drive a 1990 Volvo 240 sedan with the odometer broken at 264k.

This car is also lowered and straight piped.

I've spent weeks on multiple forums, and have spent quite a bit of money with no solution!

To the issue at hand:
Whenever I drive faster than 40 MPH, this whistling noise develops.
It ...