After a lot of steering repairs, I have looked at a lot of steering boxes. I notice that the housing of the 2wd boxes look the same as the 4wd box, but that the pitman shaft is splined differently for the different pitman arm of a 2wd. Everyone here says that you need a 2wd box for crossover steering, but I can't figure out why. Couldn't you take the pitman shaft of a 2wd and put it in a 4wd box? Or is the turning radius also different? Just want to know what the real difference is. Thanks guys. (and gals).