Hi guys. Firstly, I'm sure this has probably come up before and I've tried searching the forum, but I haven't found anything and I'm pressed for time. Basically, I had a Sachs clutch and Loba single mass flysheel installed yesterday by AmD Tunning, Essex. I delivered the car to them with nothign more than a slippy clutch, but when the installed the new kit and took it for a test drive, they allegedly encountered imeadiate vibration coming from the rear diff and qustioned me about it. So long story short, I took the car for a quick test drive and found that there was what I would gauge as a sever vibration, coming from the diff it seems, that could be felt through the entire chasis and was loud enough to be heard over the radio at a fairly loud volume. The frequency of the vibration was it it's most disturbing at about 2000RPM-2100RPM. Took it back to the shop, put it on a ramp, disconnected the Haldex, then took the car out again and the vibration was completely gone. Suggesting that it is rear diff related. Theories so far are either: A. The Haldex pump has failed and thus the diff is engaging unlubricated B. The diff is stuffed. C. Both the above. Anyone had this issue before? If so, what can you tell me about the cost of the parts, part numbers etc My car is an 2007 S3 8P. Any and all help is appreciated. Having the worst luck with cars at the moment.