I know there has been many posting online about this issue and it seems alot of people have this issue. but i cant find an answer on what it is. this issue has been getting worst every day, When turning(mainly backwards) ive been getting this grinding. it does it turning forward as well. but when going straight only happens once in a while. The transmission is new(4l60e), The u joints are new. i bought new wheel bearings but havent changed them out yet. please someone help me out here. I changed the differential cover gasket about 2 weeks ago cause it was leaking and i have been getting some vibration from the rear, so i changed the fluid with lucas gear oil, on the back is specifically say needs no additives. it has 2:73 gears(stock). if any question please ask and i will respond immediately. thank you.