2003 Ford Fusion Noticed Last Day That Put 3 Into Reverse Squeal About 2

I have noticed in the last day or so that when I put my Fusion 3 into reverse a squeal (about 2 seconds duration) or squeak (as a squeak length should be) happens and sounds as if its coming from the rear right hand side/ rear center of the car. It's a 1.4 semi auto. Any thoughts? Not getting any warning lights or anything on the dash and it drives fine in reverse, it just the sudden start of the squeak/squeal that's got me wondering if it's transmission fluid or something simple or the durashift is on the way out ..