Considering the age of the initial thread, my response is for future references.

 

Thanks, I forgot that I didn't post my findings. I ended up re-building the rear diff (the bearings were toast), but that didn't completely solve the problem. I ended up taking the rear driveshaft in to get new u-joints, checked and balanced two more times. The first time, I was told it was within spec, but apparently spec is +/- 0.005". That doesn't seem like much, but with NAPA u-Joints, it was too much. The second time I brought it in, it was balanced and checked at a higher RPM (I think 4,000 RPM if I remember right). They also put DANA U-Joints in as well. This time, it was smooth as butter. So, now, all the vibrations are gone! Except for the front wheel bearing (I replaced them a year ago with the cheap ones); I ended up replacing one already with a Timkin, and now I have to replace the other one with a Timken.

 

Did that fix the problem?

 

Yes, all drive line vibrations are gone (damn powerstroke rattles the dash a little bit though). Rear driveshaft balance and re-build with new good U-Joints did the trick.

 

Ya, thats good. The drive line is where I was heading. Thanks for the info!

 

Yeah, no problem. The Excursion is like a 55 gallon drum, so any little noise/vibration resonates throughout the cabin and sounds pretty bad. If you are going to have your driveshaft balanced and re-built, make sure to tell them that you want it as good as possible. Also, make sure they are going to balance it at a higher speed. Most places will only to to 2,500 RPM or something like that, which is why mine tested ok the first time I took it in. Good luck and welcome to the forum. FTE is a great resource with a bunch of great members who will go out of their way to help you out.

Don't be afraid to start a new thread either if you want to work through something on here from scratch, or feel free to Hi-Jack this thread since it is pretty much finished (as long as it has to do with a vibration and nothing OT).

 

I had the same problem. Tried chasing down a vibration for months. It ended up being that I needed to replace the ujoint straps ($7 from oriely's). The ujoint was loose enough to allow the drive shaft to move 1/8th inch I either direction. Anyway, I replaced the straps and no more vibration.

 

Sorry for jumping on the end of this thread, but with all the good info already here I didn't want to start a new one.

I bought an '04 Ex in June. Since then I did the v-code/modified b-code swap, and installed Nitto Terra Grappler G2 (295/70R17) tires on ATX AX201 wheels. I also added 1" lift shackles to the front springs to lessen the rake.

I did the spring swap while the old wheels and tires were still on and had no vibration. It only started after the new tires and wheels were installed. The vibration happens between 65mph and 75mph, but it comes and goes. The odd thing is that while drive on a straight-away the vibration may not be present, but after leaving a curve in the road the vibration appears. Then after going through another curve the vibration may go away again. This intermittent vibration pattern continues after each curve no matter if it is a curve to the left or right.

I've had the tires/wheels road force balanced 4 times and the vibration changed from steady to intermittent, and from 62mph to 70mph.


The vibration is quite maddening.

Is there something I should be trying different? Why does the vibration come and go with each curve in the road?
Thanks for any help you can provide.

 

Mine does the same exact thing. Can be running smooth as glass on flat ground, load or no load or slight load and all the sudden starts vibrating. Hit a bump or turn and sometimes smooth as glass again. No real rhyme or reason to why it starts or stops vibrating. All bearings and linkage has been replaced