New U Joints - now have vibration..???
 

2002 4dr , 4WD: installed new U joints on front and rear driveshafts....used torch to get glue out, new ones went in without any problem. But now have a vibration....can feel it upon taking off from a stop and really feel it on the highway.

Question: at the rear diff, there was a clip that went over the U joint and snaped part way around the cup base on the two cups that went to the yoke on the diff. There are no tabs on the yoke to hold or center the cups...I assume this clip centered the cups in the yoke. Of course the clip broke due to rust, so I just centered the cups by eye and tightened down the straps, everything seemed fine....until I drove it that is.

So, is this clip necessary?
Yes I put grease into the U joints...but could not get grease out of all four cups seals.
Taking front shaft off and going for a short drive to see if it is the front or rear driveshaft causing the vibration tomorrow.

What else...what did I do wrong????

Did you mark the alignment of the driveshaft to diff yoke at the back and to the splined yoke at the front to make sure that they went back on the exact same way?

Can you take a picture of the clip you are talking about? I just can't picture it.

I did put the rear driveshaft back in exactly as it came out. Not sure why, as I would think the shafts are balanced off the vehicle anyways (?).

This clip was a small thin flat piece of metal with short tangs on each end that went into a second groove at the base of the cups. The clip went between the two cups that were strapped into the rear diff yoke. I believe I tossed it as it broke getting it off. Lots of rust on the shafts as well. The balancing weights were still welded onto the shafts.

Thanks for the response.

If the front splined yoke and/or connection to the rear axle got rotated out, it can cause a vibration. Don't ask how, just know that it can. Been there, done that on a few different occasions.

Still going to remove the front shaft and go for a short drive to see if vibration is still there. Depending upon that I will try rotating the spline and yoke orientation and re-install shafts to see if I can get vibration to go away.

Thanks for the hints.

Without a splined slip yoke on the rear shaft, you can't get the u-joint angles out of phase as on some others makes, so doubt that is the problem. Not sure on the front as have not pulled mine yet.

Your new u-joints should have came with new "C" clips, and yes even on the cups with the straps, they need to be installed to center and make sure it can not sling a cup off regardless how tight the strap bolts are.

Where the u-joints really tight after install? Sometimes this can be an issue if things don't line up just right.

Did you drop a cup? Possibly lost or dislodged a needle bearing?

What brand of U-Joints?

Both front and rear shafts have splined yokes at the transfer case. On the rear once I got the U joint out of the yoke at the rear diff the T case slide right out and I was able to put the rear shaft back in at the same orientation, not so on the front shaft. The U joint at the front diff came right out, but the splined in I ended up having to tap out while rotating it. I believe I had the orientation correct when I re-installed, but perhaps not.

The U joint brand was Precision.

I installed clips around the cups where they could go. It is just that at the rear diff, there are no tabs on the yoke to hold the cups in position, just smooth. The front yoke has these tabs. The clip at the rear that broke I think was just an assembly aid to hold the cups centered while installing the straps. This clip was thin, and did not ends that went into the cup grooves did not go much more than 1/4"...at least from what I could see after it broke. It was all rusted, which is why I replaced everything.

The u joints move freely at each joint. I did take the rear diff U joint out, several times using the large C clamp, and I noticed that I did bend the yoke. So I put a large bolt between the yoke ears and spread it open until the U joint grooves would accept the clips and sit fully into the groove. Before one clip was not in the fully in the groove.

Have not put rear shaft on yet and road tested...that will be shortly. Hopefully I do not lose T case fluid by driving without a front shaft?? I will be able to tell right away if the vibration is still present or not.

Stay tuned.

UPDATE: After removing and re-installing the three rear driveshaft U joints, spreading the yoke and taking alot more care in installing the U joints, I put just the rear driveshaft in and went for a drive.......NO Vibrations. Tomorrow will put in the front shaft which I have already spread the yoke and re-installed the J joint and see if the vibration is still gone. Hopefully so.

Spoke too soon:
With both front and rear driveshafts on, took it out on the highway and beginning at about 67mph....vibration is very noticeable.

Took front shaft off and again out on the highway, vibration not as quite as bad, but still there.

Only thing I can think of is to have both shafts balanced. Sure sorry I replaced the U joints....thought I was doing something good.

I had the universals replaced in my 96 blazer on the rear driveshaft and the transfer case started to leak replaced the seal but it still leaks but not around the seal but from the inside of the spilne yoke....