Can't see your sig man I'm on the mobil theme .lol. how about the driveshaft. Carrier bearing. ? Man I'm just trying to brain storm to help you a bit lol

 

I appreciate it, but I have tried a lot areas already. Some people say, "well hey its a truck" But still it should ride good with and without stuff in the bed. It probably wouldn't hurt to try adding some weight to see if that changes anything.

Driveshaft is rebalanced, new u-joints, new carrier bearing.