I made this quick video of my failing SADS while I had the van up on ramps changing the oil today. I had to rotate the video so the orientation is odd. You'd see it this way if the van was laying on its side.

I'm twisting the shaft with one hand while I hold the camera with the other.

I'm not having any symptoms with this van yet. So not all the rubber bits have failed. I suppose that I'd have to rotate the shaft to inspect all the segments, but I spotted this one right away so now I know I need to plan a repair.

This van has 278k on it and there's no record of it having ever had its SADS replaced.