38 1.5 ton You understood expansion joints on the road,you know bumps ?? On your kingpin jack it up till it clears the road then shake it see if there is slack. On your thump may need to balance wheels. They say oh don't need it on big bolt,well you sure do !! Also on your kingpin when that truck is on a level surface you can see your camber(in or out at the top of your wheels on the front) it's subtle but there. Next when your driving all the rubber warmed up flat spots worked out you can "feel " the slight slack in your front end also might check your toe-in. I measure toe-in with 2 yardsticks at the bulge of the tire spindle level no more than 1/4 inch less in front than in back. That toe-in can make a big difference in how it handles. good luck fix
