Over the past several thousand miles, my truck has developed the "slip/bump" in the driveline. When braking, just before the vehicle stops, and when taking off from a standstill, there would be a progressively-worsening bump. At first I thought it may of been my rear brakes draging/sticking. But after looking over the TSB's on motorcraftservice.com, I found that my symptoms matched exactly to one of the open TSB's for my truck. I took it in to the dealership. They pulled the driveshaft, and found that there were chipping flakes of metal on the yoke. They ordered a new driveshaft assembly, and installed it.
I just picked it up yesterday, and so far the probelm is completely gone!
As an added & unexpected bonus, I think it also solved another problem that I've had for over a year... There's always been this gawd-awful humming sound in the morning when my truck is cold, and I'm completely stopped. I've had it in for service multiple times for this. Each time, they suspected it was the muffler system. They replaced everything from the cat back TWICE, all to no avail. The funny thing is that all along I've told them that it has something to do with the drivetrain, not the muffler. They insisted that it was impossible, since the driveshaft doesn't move when the truck is stopped. "Factory trained techs" huh??
Anyway, main thing is that all is good now. I can go back to loving my truck.