I have an 06 F-150 with a 6" Rough Country lift. I have a really bad shake at 65-70 mph. I just went and got my wheels balanced and all the tires checked and everything in that department is fine. So after doing all that, I noticed the shock on the passenger rear side is moving and I believe causing the wheel to bounce and give me the shake. I think the bushing on the top is bad and I just want to know if you guys think that could be the cause. Thanks