Hello! This post is still relevant, so I'll post my solution here. :)
I had the same problem and the wheel did not feel or hear different physically.
It seems like the person above me just looked at his headset after disassembling it which was his/her mistake.
I did the following; Removed foam, removed 4 screws, removed the next 4 screws.
Everything looked exactly like it should, even the wheel. HOWEVER, I still removed the wheel and placed it back again. I scrolled the wheel and it scrolled like before, so I put on the first case part, with 2 screws, started the headset and the wheel worked like it should again.
To save yourself pain, when you put everything together again, put the screw where the wheel is first and don't screw too tight, you might want to adjust the wheel again then. Once you have that right, screw the next 3, put on the foam of the last case protection before screwing it back on!