Hello there! Mine has a problem too.
The problem is:
1 - After I start up the system the calibration process ends up in a loud and endless vibration. It wont stop unless I grab the wheel hard. (see the video please)
I havent seen any calibration videos on the net so I dont know if its normal, but I dont think so.
2 - In GT5 the wheel is going crazy in the straights and even if the car is stopped. Please see the video for further understanding:
http://www.youtube.com/watch?v=pEGnWnJQ-mk
Any ideas?