I am skeptical about shops suggesting parts replacement for reliable parts.
How well do you know the history of the truck? The thing which rack and pinion steering units are most sensitive to is fluid type and quality. The first R&P that Ford used in the 80's all are ruined when they have cheap transmission fluid put in them. The fluid ruined the seals, and they leaked badly. There are countless transmission fluids, there are undoubtedly lots of types which are bad for steering systems.
I have not heard about any problems with later R&P(racks) but I would first check condition of all steering parts, general appearance etc. Then change the fluid to a quality power steering fluid, not the cheapest available. I have been using Valvolines durablend PS fluid since the early 80's, when I wondered why transmission fluid would be used in the PS in the first place.
Find a power steering fluid additive, if you can get the Lubegard brand, it is excellent, it's a tiny bottle that I use in all my vehicles.
Please don't waste any breath discussing what some manual, any manual, any expert says about recommended fluid. From the moment that power steering fluid was invented, transmission fluid should never have ever been recommended for a power steering unit. Good luck,
