1999 GT noise

Sounds like a whining air/wind tunnel noise.. heard loudest between 2-3000 RPMs.. loudest by the firewall and is heard in or out of gear, with or without air,radio etc... any ideas???

I'm having a similar problem with my 1999 Mustang.
It has 127,000 miles and about 1,000 miles ago I started hearing a roaring sound. It makes the noise most of the time but between 45-55 mph and 75 to 80+ it's LOUD!

I carried it to the Ford dealer, they determined it was a bent rear axle and charged me $1,300. Nothing was fixed by this repair so after expressing my dissatisfaction they refunded me $800.00.

It does not make this noise when I'm turning harder towards the left.

I thought it might be coming from the left front but I can't really tell. It is coming from the left side it would seem but could be the rear end.

I had the rear end fluid replaced when they put the rear axle in.
I'm thinking about having synthetic fluid with some slick50 rear end product put in it.

I thought it might be the tires.
I rotated the left tires and this did not change the sound at all.

The transmittion fluid is full. I had it serviced 5 months ago with all new fluids.

It's driving me insane.
Any ideas would be appreciated.

To diagnose a problem.... especially a noise over the internet is one of the most impossible things to do. Some1 who knows what they are doing needs to drive the car to have a good guess as to what is causing it.

Mine was the heater hose.. The restricter plate inside the hose was worn and it is up by the fire wall. The sound was loudest between 2000 and 3000 Rpms..It was loud enough to hear over the radio. The mechanic told me that he has had seasoned mechanics change out transmissions thinking it was the problem.