Before I start tearing things apart, can someone please help me identify this high pitched rattling noise when I am reversing? It kind of sounds like a loose bearing tumbling around. I can also hear it going forward but it's more intermittent, not quite as loud, and it's accompanied by an occasional chirping noise. There is no noise when coasting in neutral and the gearbox and clutch seem to be working fine. I put the car on jack stands and ran it in reverse to pinpoint the noise. It seems to be coming from an area around the pot joint and differential on the right hand side. I've included some video links for reference. Has anyone heard a sound similar to this? Any ideas what it could be? I recently replaced both diff oil seals and didn't notice anything unusual (the noise was present before they were replaced). There is a nominal amount of play when pushing/pulling on the driveshafts. It's a 1275 MKIII Cooper S. Any help/advice would be greatly appreciated!