Steering Vibration

[RGuzz]

Still with a vibration felt through the wheel while driving. Not thought
to be wheels or tires. (Balanced, rotated, etc.) Entire front end looked
at closely including axles,bushings, tie rods, ball joints, okay. This
vibration is always there no matter what position the steering wheel is
in. Rough roads transmit a more evident vibration. Could this be in the
steering box somewhere? Where to from here?
BTW, engine, trans, diff mounts also checked and okay.
Rich
235k miles