One thing nobody's mentioned is the shaft-to-box coupling. It's a bell-shaped coupling that sits on the shaft of the box and connects to the steering shaft. Frequently, the square bearings inside wear down against the shell and create a lot of slack. When I replaced mine, it removed 1/4"-1/2" of slack at the wheel. Just turn the shaft with your hand while you watch the coupling, I guarantee there's some slack there.