[Overdriven]

I meant the bar that goes through the arms and mounts them to the frame of the truck. Looks like CPP calls it a cross shaft. If the cross shaft bolts (not the ones going into the frame, the ones on the end of cross shaft) are not torqued the same on both sides of the truck one side will not move as freely and the truck won't settle the same on both sides.

If you hear creaking a bushing may not be lubed properly. Or the bushing wasn't installed properly or the cross shaft bolts tightened wrong causing the bushing to deform. I'd start with the torque specs and procedure for tightening the cross shaft bolts, loosen them up and do it over again. If that doesn't fix the issue then you're going to have to pull the arms to inspect, possibly replace and relube the bushings.