I have a 1992 Volvo 960, 138k. For the last 18k, I've been getting noise out of the rear end, that gets louder or softer at different speeds and when turning on the highway. After eliminating the rotors and rotating the tires, the noise is still there. Seems to be consistent with rotation of the wheels. I'm giessiong its the bearings, but don't want to blow another 900 on it, sas suggested when dealer said I needed a whole new wheel hub assembly. What do I need, and can these bearings be repacked in my driveway?