BioMax
+1y
Jay is right about the caster and possibly the shocks, but realize that dropped spindles have more tierod geometry issues then the stock spindles do. Unless the issues occur while you are driving the truck 1" off the ground, I don't think that the spindles will be the cure. Have you made any other suspension changes? Flipped ball-joints, custom arms, changed the pivot points... Anything?
At this point, if you haven't made any of those changes, I would bet my breakfast burrito that the heavy wheel/tire combo is the culprit and going with 22's is only going to make it worse.