[Vinnie]

I’m trying to think how to check for lint in this long section

Is the tubing visible? It's usually thin 4"dia. aluminum in 4 ft. sections. One section end fits inside the other, then a couple screws.
Easy to take apart. Just be sure to index the sections so you can find the screw holes putting it back together.

[roofgoat]

I just got up on my ladder, unscrewed the clamp that holds the vent accordion tubing to the main solid long pipe that leads to the outside. No blockages there even though it was a 90 degree angle. Actually the accordion flex tubing went down, than up slightly to connect. I dragged the accordion tubing down the solid pipe more so now the angle is less severe.

I took a flood light and looked down the solid straight tube, I saw nothing. I'll use the floodlight to look just where the flap is outside and give that a look.

I'm buying that Lint Eater soon too just to be safe.