ok i have this roaring sound when i get up to 40 plus, driveshaft checked good, u-joints checked good, transmission checked good. i took the car to two different shops, first one didnt have clue, second one said rear wheel bearings. Gunna give it a shot since i didnt check them out. my question is what do i need to change these out, obviouly i need bearings, what else? also any tips thanks.