Dealers are not always correct. A steering column is pretty rare to have go, unless the truck hit something hard or has been in an accident, if it was mine, I would replace the linkage I posted a picture of first, but then again I haven't seen the truck and am only going by what you have mentioned. Did you watch the video I posted early of how to replace the steering shaft, it explains the clunk in the steering wheel which I think you mentioned you have, changing the steering shaft( the one pictured) usually takes care of that clunk. Good luck.