It's been a while but it looks as if we got the steer problem squared away.

We jacked the machine up and rocked the steer wheels back and forth by hand. This was done both with the engine on and off. Not much movement either way.
All tie rod ends, king pins, and bearings seem to be decent. Some wear but nothing to be an issue.

Then we checked the steer cylinder itself and it was tight. There was no way to move it manually, even with leverage.
Also, there is no type of fluid leak what so ever at the gland seal.
Now I'm starting to doubt my theory on the cylinder.

So now I reconsidered the hydrostatic steering box. While the machine was jacked up, I turned the steering wheel back and forth.
I noticed that sometimes the wheels would turn one way but they would not return when steering lightly at idle.

If you increase the engine speed it would steer the wheels both ways but sometimes the steer wheel would make one full revolution with out moving the wheels. If you rock the wheel and let off the gas pedal then the steering action would return.

Sometimes though you could still make the steering wheel travel two revolutions without any action on the steer cylinder. Evedently a steering box issue.

After doing some research on the steering box, I found out that there are built in check valves as well as hydraulic splines that can wear out over time and fail.

Long story short, I replaced the steering box. Problem solved!

Plus, not only has the wander problem been taken care of, the forklift seems to steer much easier in general. It goes to show how something can slowly wear over time without notable change.

Truck Tech, Thanks for your input.

Jake