Chris - Yes, that's it ... if the amount of free play seems excessive.
It wouldn't hurt to have a mechanic who specializes in trucks try it to see if they think the free play is excessive. Or, have one or more people who drive medium duty trucks a lot try it. (Either group may not have a lot of experience but multiple opinions wouldn't hurt.
The screw in the upper left of the picture looks like the one idiots like to fiddle with if they (unintentionally) want to really mess things up. Or, the one in the lower left of the picture below ... I'd have to look at the actual gearbox to tell you which one people tend to mess with.
Depending on the miles on your vehicle, the gearbox could just be wearing out.
I pulled that off my commercial account ... for a '79 B300 w/ 360/5.9 engine and power steering. CarQuest p/n 27-6542 ... any parts store interchange can use that number.
You're gonna want to look and compare to make sure it's right. Measuring mounting bolt spacing, hose connections, and pitman arm shaft would also be a good idea. (This should be right but I've learned anything -- and weird -- is possible on older Dodge trucks.)
Interestingly, the power steering gearbox costs less than a manual steering gear box ... 40-50 percent less. (i.e., a little more than half the price of a manual gearbox.)
While you're at it, you might as well change the hoses, especially the pressure hose. (The return hose lasts much longer than the pressure hose ... but an old, deteriorating one could be flaking off inside the system.)
Also, drain and refill the pump and reservoir, if you don't accidentally do so while replacing the gearbox. (An oil drain/catch pan would be a good idea ... hint, hint.)
