I just finished a clutch job and everything seems fine except I have a weird whine(sounds like it might be coming from the back right). Sounds like rubbing metal and it sort of warbles. It also only happens if I am actually reversing, if I am in reverse and sitting still I get nothing, even if I rev the engine.

update: Ok, I got somebody to drive it while I was outside the car so I could listen and locate the noise better. The sound only happens when the car is moving backwards... it can be in neutral and rolling down a hill and it will make the noise. It's also coming from the front right. I'm guessing it's something in the brake pad or something similar and will rip it apart to clean it out when I get home.

 

Turns out it was just the brake dust shield on the back of the rotor, apparently it got a little bent and was rubbing the back of the rotor.