I am having the same problem but I can't seem to fix it. I am new to the sport and for the first time I switched Tires on my bike. When I put the rear wheel back on, I noticed that when I shift to the the largest rear cog, the Guide Pulley is resting on the COgs and making a grinding noise. I tried adjusting the B-Screw to create space between the two, but it maxed out and didn't work at all. Another thing I noticed was that if I go on the small-small combo, the Tension Pulley becomes horizontal to the Guidepulley, and the chain actually rubs against itself at the guide pulley.
Did I do somthing wrong reattaching the back the wheel? I checked and the wheel is completely seated in properly, and the chain is on correctly.
Any help would be appreciated...