All shafts are in phase.
All driveline angles are well under 3 degrees.

I guess I have not explained this good...I am agrivated and this is a PITA!!
SO let me try with the facts again:

-Vibration starts at 60, gets worse as MPH is increased (only been up to 82MPH).

-Vibrations does NOT go away when coasting in neutral at those speeds.

-The vibration is a heavy drone and minor shimmy at first...then around 65 it feels like a wheel is coming loose, and shaking the truck.

-The tranny is a ATS with about 18k on it.

-The vibration is the same with the truck running on stand with ONLY the first shaft installed (this shaft has the center bearing on it). Every part on this shaft is new and balanced.

-Yes it has done this since I got screwed....oh, I mean bought it used from a very honest guy! The truck had 398k on it, I have the paperwork for the tranny to confirm there is 18k on that.

-With the yoke installed, I could move it enough so I could feel it and see it move in the bushing.

-I measured the yoke, it is 1.710" at the ends and 1.704" where it rides on the bushing. I have no accurate way to measure the bushing ID with the output shaft in the way.


Did this clear the picture up?

 

But busboy it did it with the rear shaft out, so that rules out phasing and mis splined, and alignment unless is front joint. Not likely since no load with rear shaft out. 6BT12V, it's back in your stall again.

 

Have you spoken to the guy you bought it from? Not to be accusing him of anything, but to ask if he felt the vibe, and how long it had been in there?
Both TCs I had in my ATS tranny vibrated, RPM dependent, not related to speed. I'm just wondering it it started when the tranny was put in.
Have you tried running it with no yoke in the tranny? You might lose a little fluid, but if the vibration is still there, you are one step further to tracking it down.

Chris

 

Installed new slip yoke today...not much if any difference on the vibration....BUT, I think I am on to something else though....finally, may be able to figure this out....

 

So you are looking into the OD unit?? The OD unit can be removed and serviced without removing tranny.