1995 FLD Steering is hyper responsive

How does the track going down the road at least 50mph? Only thing I can think of is to check your alignment in front end. You can easily get a close enough idea of your toe with a tape measure. You should have slight toe in. Measure distance from rear of both tires at centerline and then do the same at front of tires. Centerline to centerline. If you don’t have someon to help hold tape, just go off opposite side of center tread. That will hold the the tape for you.
You can jack up truck and check king pins and wheel bearings but unless they have some serious play in them, I don’t suspect them to be it. Gearbox sounds fine
Nothing wrong with steering wheel, steering wheel goes from shaft to gearbox

 

Check all of the front end components for binding. This can be anything from a frozen steering u-joint to a frozen king pin. The issue your likely feeling is the constant over-correction due to the inability of the front end to return to center on it's own. This condition can feel way worse than a lose component depending on which part in the system is stuck.

Start bay jacking up the front end and put the axle on support stands. Try to rotate the wheels through the turn range left to right from the wheel end as you should be able to do this by hand from lock to lock with minimal effort. Rust leaks or staining at any component is a dead giveaway of a worn/frozen /loose part that has lacked proper lubrication and or is failing. From there start disconnecting components to isolate which part is binding.

Dont forget to check lower steering ujoint inside the cab if equipped. That one never gets attention. Depending on the age and condition of your truck it could be anything..........

 

Power steering issue?