Looked at the truck again this past weekend. Removed Borgeson Steering Shaft to inspect. Checked ujoints and coupler, all tight. Also checked for slack in the slip joint between the upper and lower shaft. Nothing there either. Put it back together and no more clunk this morning on the way to work. Then I remembered that I had fixed the same clunk a few years back by doing the same thing. I am of the opinion that where the Borgeson attaches to the steering column shaft, over time this connection becomes a little loose. It's not loose enough to reach down and move with your hand but as the differential, body and frame flex during take off or stopping it causes this connection to shift just enough to be felt in the steering wheel and the pedals. BTW, I do have the bushing fix in the steering column as well. My . 02 FWIW.