well all bearings are allowed a certain amount of play. you need to determine exactly what is moving and making noise. hold the side of the cv join that goes into the t case and move the ds up and down. if there is play then it may only be that u joint and you would be good to go. if there is no play then its only the bearing. check with a place like aamco or something for a better price. shop around at reputable places. most good shops will give you a warranty also. but a bearing replacement is definitely something i dont suggest you do yourself.