Had some vibration and wanted to replace all the rear u joints. Looked and saw that one was brand new so I only ordered two replacements. Dropped the rear two part driveshaft and was checking them. The new one moves real smooth, like I think it should, one way, but when you move it back and forth the other way, it feels pretty stiff. Shouldn't it move freely on both axis's? If it should, then maybe this new one is the one that's causing the vibration. I took one of the old ones out and replaced it, but it was still in good shape. Now I only have one replacement left and I don't know whether I should replace that one that looks new or the other real old one. The one that I just put in moves with the same resistance any way you move it.

 

I just went through this yesterday. I took the driveshaft (2 pieces) out and replaced them all cause it was easier and made more sense to do so. I had a really bad vibration when I was slowing down to a stop. From like 35 till stopped. Ended up being one u-joint that was locked up one way. It would move one way but not the other. Like front to back but not side to side. They should move pretty freely. Make sure you put in the greaseable u-joints. I put in Precision.

 

I got precision too. But I only bought 2 cause the one looked to be shiny new. The ones I bought say USA on them, but the one in question says Japan. It's gotta go! I don't know what brand it is, but like you said it's kinda locked up one way. It's the u joint that is next to the carrier bearing on the very back driveshaft. Is that the one that was locked up on yours also?

 

I gotta go back out and replace that one now. It's after midnight and I'm still at it. Of course, I ran into some problems like one of the bolts on the carrier bearing was froze up and the nut stripped. I had to cut it off and then find another nut and bolt. Also, I had a heck of a time getting that one u joint out.

 

Just a little advice you probably already know , mark the drive shaft front and back , they must go back together in same configuration because that is the way they are balanced . If you change the line up you will experience a vibration in the drive train and if this happens , because you forgot to mark it , just drop it and give it a 180 .

 

Just finished replacing all rear ujoints and still have the vibration from 25 to 35 mph. Anybody got any idea what could cause that? I put new tires on the front and balanced the rear. Also it has a new front driveshaft.

 

Look at the carrier bearing is it centered on its mount , some of the guys lower it a little by shimming it down and that has helped . Drive it around the block and check it for places that are warm caused from binding . If after all that you still have not found the problem put it up on a hoist and feel the drive shaft while running to see if it is coming from there . Are you sure you put it back together the same way it came from the factory if not drop it and give the center universal a 180 . That is all I got good luck

 

Thanks John. I'll try it on a hoist when I get a chance.

 

Finally broke down and bought a $158 carrier bearing from the dealership thinking that it would not help any because mine seems fine. I just replaced it and to my surprise, the vibration is history! My truck drives better at all speeds now. The old bearing was in good shape, but the rubber surrounding it was just worn out I guess. Oh yeah, I just beat the old carrier bearing off the shaft and used a pipe to drive the new one on. It wasn't too hard really. Now I can move on to better things like adding more goodies.