Hi to all,

Yesterday I bought a '96 E-250 with a 5.8L V8 89K, don't know which transmission is on it.

On the way home, on the highway, the van would begin to vibrate progressively stronger and stronger. It would begin to be noticeble at 45 mph and would get the worst a 65 mph. from 65 to 75 it would begin to wind down. Above 75 it would start again but not as but as the first band. The vibration was kinda like going over thin rumbble strips and hummingat the highest speeds, from beginning to end, felt on the seat and not on the steering. I was afraid that the transmission or the differential was about to blow up.

After reading all the related threads here and on the newsgroups last night, I put the vehicle on blocks and reved it up through 60mph. (Too skeered to go beyond that on jack-stands).

While the van was propped up and running at the above speeds it behaved the same way as it did on the road. I also looked at the wheels and they were straight and showed no wobble side ways or up and down. Then I noticed that the drive shaft was wobling or oscillating visibly and mostly at the rear near the U-joint. The input shaft to the differential appeared solid with no wobble.

I think that that must be the culprit.

Those are the symptoms. Now for the cure. All I can think of is to replace the U-joint. Will that solve the problem of the drive shaft oscillating and in turn making the whole van vibrate? If that does not do the trick what is the next step?

Any ideas?

 

well if that doesent work id say a wider diamater drive shaft

 

Replace the joints. Mark the various sections of driveshaft and put them back together exactly how they came apart with new joints. If there is still vibration, get the driveshaft(s) balanced by a machine shop that handles this.

 

Thanks for the advice!

I just got the joints, and this weekend I'll get them on the truck. Hopefully that's all it'll take. If not, I'll get the drive shaft checked.
Once it runs smooth it'll be great! ... 351W Baby!!!.

Thanks again

 

Well I got under the truck and pulled out the rear u-joint and drive shaft.

One of the cups of the u-joint spider (the part you replace) was so dry that it had pulverized the roller bearings that it contained. There was the culprit, that was causing the drive shaft to oscillate and the van to vibrate.

I had replaced many u-joints before in vans and cars because the drive shaft would have fallen off soon thereafter, but never was there a vibration like that as a tell-tale sign.

After installing the new u-joint, and test driving the truck, is as smooth as an LTD.