Okay, I binged today. Not on food. On cleaning the lint in my laundry room.
I noticed the lint trap didn't go in all the way. Odd. Always had before. Cleaned it out. Still doesn't fit. Pull it out, look inside. Ohhhhh. Lint stuck in the bottom. I reached in the tight slot and pulled an 8 inch long 1 inch square patch of solid grey lint out from under the trap. No wonder it didn't fit. Put it back in. Still doesn't fit. Look closer. More lint. Take out all I can by hand. It made a pile roughly equivalent to the size of an airline pillow. I can't reach the rest.
Get the screwdriver, remove the lint trap cover. Reach in as far as possible and realize there is a cavernous space below the lint filter completely full of lint. I cleaned that out by hand. No wonder the drum was squeeking. It had no room to move!
Now please understand, we regularly clean our lint trap. How the dryer got this way was the question. Was my dryer exhaust blocked? I'd have to move the dryer. But alas, the exhaust hose is not long enough for me to get behind the dryer. I'll have to move the washer and come in from that side.
Now, if you have ever moved your laundry pair, you know what I encountered. Five years we've lived in this home. I've moved them out once to clean. It was as bad as I remembered. So THAT's where the red sock went!
Got the shop vac. You can pick up anything with a shop vac. Even bottles of shoe polish, I come to find out. Thankfully, it didn't make it into the vac hose. And the old dryer sheet plugged the hose just before the tank, so I could remove it cleanly and restore suction.
Perfectionism is that voice that says, "Now that you've got it all pulled apart, give it a good washing back there!" After all, so many of my friends notice and judge me by the condition of the floor underneath my washer and dryer.
But clean I did. I even unscrewed the back panel off the dryer to vacuum inside where the motor sits. I wiped down the hoses and cords, I vacuumed and washed the floor, I cut my thumb reaching into places no hands were meant to go. And just as I was about to push the dryer back, I realized.... I need to check the vent. It was relatively clean, not blocked at all.
So I did not solve the mystery, but I had a good workout and now there's no need to take that trip to the Y.