so me n my cuz just put in new axle seals and a pinion seal in my 8.8. i drove it home, and on the way it started to make a reall baddd grinding like noise.. its speratic, but it only does it when the truck is coastin/rollin.. as soon as i give it gas it goes away.. we did axle seals cause one was leakin and it gummed up the right rear drum assembly.. the pinion seal we replaced cause it was jsut leaky.. we didnt pull the diff out, he just pulled the pinion flange off and changed the seal..I have no idea what is causin this noise.. please some one help me its one of those sounds that says dissasster is comming!!