Andy - raise the car and grab the tire and see how much play there is if it's a bearing or spin the tire and listen, as for the bearing they are nightmares to replace ask around, the tool is $249 from bavarian and worth it! If it's a "joint" it should have a little clunk back and forth on rotation on the outside joint and "whir" on the one near the differential (two types of cv joints). Good Luck.