Brakes Grinding in Reverse...Why??

Have an 00 GT with 03 Cobra brakes up front. When in reverse, there is disctict grinding sound coming from the front brakes. I have noticed that it is louder in the interior than the exterior of the car and that it only happens in reverse.

When brake pressure is applied it goes away. It is also not side specific. I have heard it on both sides but usually one side at a time.

I have not had a chance to crawl under the car to look as I have been replacing water damaged flooring in the house do to a faulty toilet, just looking for ideas on where to look and what to look for.

Thanks

why the IRS if the noise if coming from the front brakes?

I figured it was implied since I addressed the front brakes specifically. Its been changed.