A few months back I replaced the U-joints on my rear drive shaft of my 92 4x4 ext. cab 5.2 dakota. The drive-shaft on my truck is a one piece. I noticed that while my original problem with driveline vibration got better for a while after the repair, it is now worse than ever.

I when I re-assembled the driveshaft I did not mark the position of the slip yoke going into the T-case nor did I mark up the slip yoke position in relation to the drive shaft, nor did I mark the the yoke on the rear axle in relation to the one on the drive shaft.
(Stupid me)

I figured it wouldn't make a difference since my shaft is a single piece it couldn't be reassembled "out of phase" but I'm starting to think I'm wrong.

Assuming how I put together the dive shaft was incorrect I should be able take it apart and re-assemble the slip yoke and driveshaft 180 degrees relative to how it now is. Then test my tuck for vibrations, if it still occurs then remove the driveshaft from the rearend, rotate 180 degrees and reassemble and test again. This should help me trouble shoot/solve my problem, yes?

I should add that I plan on replacing the U-joints again. I should also add that the balance weight is still on my driveshaft.

 

ive heard of that but on both my dakotas ive never experienced it. it could be that the rear ujoint is slightly out of place or that there is something else wrong. I dont remember if the transfer cases had a key on the splines or not but I know the rwd autos do. the ujoints on the front might be starting to go now or the rear ones went out again. I would check the front ones first.

 

Are the snap rings installed on the rear u-joint where it sits in the differential yoke (assuming yours uses the same u-joint mine did)? If they aren't, the joint can get off-center and cause some pretty bad vibration.

 

Ok, well my plan worked and my drive line is almost vibration free! I'll say almost because there is still a little vibration left along with a horrible grinding noise. I was able to confirm that my output bearing on my T-case is shot probably from all the vibration from the u joints. But the truck now runs very smooth at freeway speeds and the noise and vibration from the output bearing is only slight and during load.

BTW: The slip yoke on mine had a keyed spline but I did not see one on the output.

Anyone done a t-case output shaft bearing? I looked up instructions on the 1995 dakota owners manual on the FAQ page and it looked pretty easy, no need to pull the whole case out.

Also checked front u-joints, they are fine.