I try to make the post title informative, but I have no idea how I'd word this. Crawling under my truck the myriad times I have lately, I looked at one of the front axleshaft u-joints. I'm sure they are original, they look like they are part of the shaft. However, I noticed where one cap comes through the shaft, whatever is coating the shaft there (paint, plastic from the factory u-joints, rust?) is "cracked". Basically what it looks like is that the cap has started to move around just a tiny bit. It's not a crack in the metal or anything, but I'm curious if anyone else thinks this is an indication that the shafts need pulled and these joints need replaced?