happened this morning, was parking into lot, got in middle of 2 parking spaces so i put it in reverse to correct, then while turning left, i backed up.. screech! first time i hear metal grinding noise while in reverse?! I tried it later that day and nothing.. wtf?! has anyone experienced this, or heard of it?

 

i had this issue but im not sure if its the same as yours, mine was from the rotor guards hitting the rotors. but if it sounds like its metal on metal i think it'll bee your braking system

 

More than likely it is what Evokid8 had said. If it happens again, stop where you are right as you hear it and check.

 

^ ok, ill do that next time..