I hesitate to wake this thread, but I just dropped my MS back in for semi-emergency service. A terrible grinding noise under regen, but completely silent during acceleration. SC thinks it might be a rock stuck in the rotor, and I'd definitely be relieved if that were the case. But it certainly sounded more like a drive unit issue - especially given the ability to modulate based on energy input. Some other issues so they're keeping it for a while. I suppose I'll find out soon - but I haven't heard this particular report before.