2000 F-150 4X4. At very low speeds when maneuvering , accelarating slowly from a parked position, driving slowly over a bumpy road, I feel a clunk or a rap in the steering column. This is a feeling, not a noise. It can occur in both a left and right turn.
At higher speeds over the highway steering seems normal and there is no clunk.
Replaced ball joints and tie rod ends last week. Didn't help.
Any ideas?

 

This problem turned out to be a lower steering shaft. Dealer replaced. Now OK.
F75Z*3B676*CA Shaft Asy-Stng Col Lwr

With labor $257.

Not a common problem since '97.