I AM the owner of a Falcon AU Series III that has had the same problems with a clunking driveline another reader had in his BA XR8. Mine has done 95,000km and is out of warranty, but on many occasions I have had no joy with the service department. Each time the fluid has been topped up or an adjustment made, but I have been told that they could not find the actual problem because no error codes were coming up. It was interesting to read that Ford has been aware of this problem since 2001, when I bought the car.
MY understanding is that the problem is caused by a design fault in the diff itself, so it would not show up when the mechanic checks the codes. Though the problem may be reduced if the auto changes are softened, that doesn't really address the problem. But I am told Ford is at a loss as to how to fix it and the solution has to come from the supplier of the diffs.
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