Interesting. I had different issues when I had my DFGT (it would make weird rattling noises when turned to right) but it eventually died and the only things that seemed to work were the buttons on the wheel, the wheel itself stopped working.
Too bad there are no responses on Logitech forums atm. I had the same issue. When I posted posts after posts about the issues I was dealing with the only response I got was, ''reinstall your drivers''.
If you are planning to buy a G27 from Logitech, you can try to do what I did. Basically around summer time they seem to give out discount codes for their products to their loyal customers. I emailed them on their website about the fact that my DFGT broke down and eventually they gave me out a loyalty discount code (which was 50 percent for a new wheel). So keep that in mind, you might be able to get a G27 for a lot cheaper!