ok i have this annoying vibration on the hwy, tried replacing the ujoints and carrier bearing and still there so balanced all 6 tires and rotated 4, also got an alignment, still there seems like it is in the center or close to the pass side in the cab not a violent shake but enough to be real annoying, I looked at the trans mount and it looks ok so i think I am out of ideas, there is no shake in the steering wheel

 

Have you checked all the U-joints, Yokes, etc on the drive shaft? (or is that what you are talking about when you say U-joints). You could have your drive shaft balanced and see if it is in there.

 

all 3 u joints on the rear driveshaft are new and the carrier bearing is new, the yoke and slip joints were tight and the drive shaft looks straight and I saw no spots where weights look missing

 

I had an annoying vibration once and it turned out to be a bad tire...it was balanced, (several times) but when rolling, it caused a vibration. I only felt it at certain speeds. It finally came apart, so I have a new set, but perhaps a belt is broken inside and when rolling it shakes?

 

Tire shake is slower than a drive shaft as the same road speed.
My truck has the higher speed shake, I suspect the front drive shaft.
easy to remove it and drive it for a week to determine if that is it.

 

I did not know the fron shaft turned when the 4x4 is off ???

 

Is it possible that the rear shafts are not properlly phased??

 

it turns, the hubs are always locked thus driving the diff than the drive shaft.

try removing the shaft and see if the vibartion goes away. i had a really annoying vibration at 120 km/hr.

changed all three u-joints up from. 90% of the needle bearings where missing. and the vibration went away.

 

I bought a cheap dial guage from Harbor Freight and checked mine. Found it had some wobble in it. Used a ball joint press to center the U joints in their mounts and tuned out most all my vibration. You can also separate the 2 halves of the drive shaft and turn the back half 180 degrees. It might have been out of phase. It will fit together 2 different ways.

 

Front U-joints like said before. They are spinning (drive shaft) even though your not in 4wd. Same problem when I got my truck.

Good luck.

 

If you remove the shaft as a test make some marks so it goes back on the same way you took it off, a grease pen or marker.

 

not required to mark where the drive shaft was removed from, but if the yoke was removed, you would need to mark the drv shaft to yoke posn.

also if the front drv shaft is that bad to cause a vibration in 2wd it SHOULD be noticable when you crawl under neath and wiggle/shake it around...

 

OK GUYS I will check it next chance i get, thanks for the info