How long have you had them and how long did it take for the CV to wear out? Came back from wheeling and noticed a high pitched squeeling sound coming from under the truck and I thought must be a u-joint. Hmm, I wouldn't think a u-joint would have already gone out....the shafts only 3yrs old. Everything Spicer and 1350 stuff. The only think I can think is its because they are sealed u-joints. Jacked the truck up and let the rear end spin...bad noises from the CV. Pull the shaft and the ball in the middle of the CV is completely dry thus the squeeling noise. Look all over the CV and there is no place to grease it, which I didn't find when I installed it the first time. Needless to say I'm kind of disappointed there is no way to grease the ball. Now I have to see if somebody can replace it since all the d-shaft places here say that my slip yoke CV shaft doesn't exist, that's what they told me when I asked about one being custom built locally. Anybody elses shaft done this?