Neighbors ... good stuff from everyone!! My own thinking is that tire pressures should be upped at least 5#'s over stock, replace front bushings, check rear spring bushings, replace with poly and make sure that everything is tight. Was truck bought new? If not, is rear stabilizer bar still there? If it is ... replace bushings.

My own truck had the same problem. I bought it used ..... didn't catch that rear stabilizer was missing and wrong spring shackles used to lower the rear end. Front bushing looked okay, but weren't. Replaced complete upper arms, lowers were okay, replaced rear sway bar, replaced spring shackle with correct part, front end alignment and problem went away. A steering stabilizer is great idea, but it turned out not to be needed after repairs made. your neighbor, ron :-)