High pitched sound when in reverse...

Like the title says I hear a high pitched sound coming from somewhere on the front driver side wheel area. I'm not sure exactly but I think that's the area. It only makes this sound when I start moving when in reverse. Any ideas.

2000 mustang gt
5-speed
 
Like the title says I hear a high pitched sound coming from somewhere on the front driver side wheel area. I'm not sure exactly but I think that's the area. It only makes this sound when I start moving when in reverse. Any ideas.

2000 mustang gt
5-speed

How long have you had the car?

I never use reverse much; just enough to get it move then pop it back in neutral and in gear. Reverse gear in a manual trans is always/almost always a straight cut gear, and they will whine if your fully engaged and going fast enough.