Billy, the dropped diff certainly causes failure. The prop shaft was designed to always stay at a certain angle, not like the CV joints. As illustrated in the photo, there is not much room for angle change. Less than an 3/4" in play in either direction. The cuff was not meant to flex either. I would be curious for those with diff drops to crawl under the truck with a light and see how much metal deformation has occurred, and if their cuffs are ripped.(Only my front ones ripped) How many have actually installed diff drops? That would be a good survey

I do agree that even without the drop, the cuff can tear, but much the same as a CV, keep adding grease, stay out of mud and water, and it will probably last years. My wife has a torn CV boot, haven't had a reason to repair it, if the CV gets noisy, there are lots of troopers in the yard