Man O man us it nice to go down the road and not have to listen to a constant knocking from behind my head! FWIW, the TSB says to stick the foam blocks to the roof panel. That's not correct. If you do that, the only thing the foam blocks will touch is the roof. There is a brace that runs cross wise just behind the overhead light. There are two foam blocks already glued to the headliner that sit below this brace. Over time the headliner sags a little and a space develops between the foam blocks and the brace. As you go over bumps, the headliner bounces and the knocking sound you hear is the hard foam blocks slamming into the brace.

You need to cut the foam block in two (per the instructions in the TSB) and stick each half to the brace above each foam block. Even if the headliner bounces now, it will be foam hitting foam and so it's silent.

You gain access to the brace by pulling back the trim at the rear of the sunroof opening. The trim secures the headliner to another brace that runs all around the sunroof. You can then easily get your hand and a flashlight between the headliner and the roof facing back toward the dome light in order to get the foam blocks installed.

Don't pull any more of the sunroof trim than needed, and of course put it back when you are done. This is what it should look like installed:



At the top is the sunroof brace. Further back, you can see the dome light sticking up through the headliner. You can see the two black foam blocks that were original to the truck, glued to the headliner. Just above each is where I placed the new, white foam blocks from Ford. They come with peel-'n-stick adhesive. It comes as one block but the TSB says to cut it in two. If you turn the dome light on, it helps you see what you are doing in addition to using a flashlight. Once in place and with the sunroof trim replaced, it's all quiet!