Rear end noise

i have a 92 merc grand maarquis ls and i recintly replaced the disc breaks all way round any ways in the rear i was hearing a grinding noise so i took and bent the backing plate for the parking break back this seemed to help i drove it around and there was no noise so i parked it then on my way home from work half way hom it was back but worse and loader now im thinking its a rear end so today i check the fluid and it looks fine so if theres any one who feels my pain or nos hoe to fix plese holla oh yea the noise is like a grinding type and a growling noise

jack up the rear end,put on jack stands,chock the front wheels,start the car and with your foot on the brake put car in gear and listen ( you'l know if its your rear or not ) A second test would be to hold one wheel from turning,unless you have a limited slip differential.

omg thank u so much ive been bogleing my mind trying to find out the noise