whenever im in reverse there is a weird sound, sounds like metal on metal, but the sound is almost like a whinding sound.... my dad says brakes, but i have no clue. i figured i would just put it out here and tell me what you guys think. thanks.

 

Not the best discription but here is the things I would check.

If the noise happens as soon as you put it into reverse but NOT moving yet its in the trans.

If it happens when in motion it still could be trans or in the rear diff.

Check your front calipers. If a bolt falls out of the top caliper mount when you are backing up and on the brakes the caliper will "swing" out and contact the inside of the rim.

 

Check rear u-joint.

 

check your rear brakes too....

 

Also check backlash in your rear.