Back when I didn't know better, I drove on a bad u joint for a long time. it wore half of one of the yokes away. I was able to replace the joint and it never did give me any more problems until I sold the rig a few years later. The point of this is, I have changed a lot of u joints since then and regardless of how bad they were, the only ones that were "tight" we're when I accidentally let a needle bearing fall down without noticing it. I was able to get them in but the joint was tight and failed pretty soon. if the joint doesn't, move freely, you may have a fallen needle bearing.