Thumping or popping from front end

[Jesus_man]

When I hit a bump, my truck has a thump in the floor boards that I cannot figure out. It seems to do it if I hit a bump with one front wheel and not the other. For example, it won't consistently do it when I hit a speed bump straight on, but if I hit it at an angle, it's almost guaranteed to make the noise. Everything up front is completely stock, and always has been, except that I recently replaced sway bar bushings with poly ones. Everything there seems tight and I can't see any movement anywhere up front, in the form of shiny metal from a loose bolt or something. I have also jacked up the truck on the drivers side to wiggle the tire and I cannot get it to move at all. I guess I should try the passenger side, but it seems to be the drivers side. I also looked closely at the shocks, leaf spring mount and shackle, nothing. I better do the same for the passenger side just to be safe.

What else should I check? Truck has 95k miles on it.

J.D.