Well I had the wife jump up and down on the back of the truck while I looked underneath ( she could barely make it move) and I noticed that the mount extension for the shock was moving around. Then I realized the extra parts I had left from the drop kit were for the shock extension mount. I bolted them down good and tight and there is now a huge difference. No more hopping and the ride isn't very bumpy anymore.
I know I'm late on the reply but I have the same issue, I did everything possible to level it. Nothing worked, so I just ordered a set of Slam-air bags for the back. I'm also removing the front bump stops because I noticed the lower control arm is riding on them, I'm going to install 1" bump stops instead and see what happens.