6 psi is all you are supposed to run in rear. If you run 10 psi it will ride really rough so maybe that was your problem. Try running 6 psi in both rear tiresI found that my left rear tire only had like 6 psi of air in it so I aired it up ti 10 pis like the other on and it seems to be fine again. I will look at my control arm bushings though.
thanks for the help.