i found my problems.. when i put my truck on a buddies lift
and.. went lock to lock.. but.. actually push a bit on each lock. The axle on my truck would shift about an inch! it was due to the Long Shackles i had (two pieces of plate, not connected). I later welded a section of tubing inside.. giving it a bit more lateral ridgity. It was like night and day after doing that.

Apparently my rear sways a bit too due to the same circumstances but it was not noticable to me when i drove.