T1N Sprinter Rear door squeak from hell -FOUND!!
I have honed in on the rear door squeaking. It wasn't the top of the door, it's the middle. At the end of the video, you can see the rear door is actually cracked/coming apart, on the inside. That may be the root cause of the issue, or maybe it was the tear near the latch, which was here before I got the van and added the generator box. I'll have a body shop see what they can do or just replace the door. I am SO relieved. This thing has had endless squeaks. Driveshaft bearing, Ikea countertop, folding bed, harbor freight red end cabinet, my wood stove, all squeaked like crazy. It's infuriating when even your loudest music can't drown it out. Rejoice, no more invisible mice!