While I was changing mine out last night I thought of something concerning the vibration. Did you completely remove the prop shaft from both ends or just drop the roto end? I'm thinking it could be 180* out at the forward end (transfer case output) and this MAY have an effect on the harmonics of the shaft...

Also, there is no discernable difference in which way the lettering faces...toward the front or rear. The pic Tweak posted does however, show the correct bolting pattern as far as compressing the thick part of the roto against the pinion flange bolts as the shaft turns clockwise (if looking aft).

When you said you replaced the centralizing bearing did you mean the metal / rubber bush in the aft end of the shaft...the bush that is truly a massive B!tc# to remove without proper tools?

 

Yes I did remove the shaft completely. How can you tell if you have it in 180 off? Yes I did remove the bushing. Took 4 hours with several chisels, tried using pullers but would not budge. Felt pretty solid on the pin when I reinstalled it.

 

unfortunately there is no way to visibly tell if the shaft is 180* out that I know of... meaning no marks or anything. the bolt pattern on the txfer output shaft / brake drum is such that you can only put it on one of two ways... not four ways as if the four bolts were in a perfect square.... Try unbolting that end of the shaft and rotate it 180 then reassemble and drive to see if you still have those bad vibes.

Yeah that little centralizing bush is a massive pain... so long as the bush is sitting square on the lip inside the shaft center then I doubt it is the fault of the bush.

I can't remember where I read about the balancing of the shafts (front and rear) but I do remember if they are out of sync then vibes will ensue.

 

I did not unbolt it. The shaft slides off the splines.

 

are you refering to the shaft being off 180 in relation to the front shaft? cause if you are that makes no sense as the shafts can turn at different speeds due to the differential action of the t/c, so the shafts are never the same in relation to each other. I think the concern with keeping the correct orientation when pulling the ds is when removing universal joints, making sure the peices stay in the same orientation to each other. now if you got it off by not putting it together at the splines the same way it came off that would possibly cause problems.

 

if you need a pic of how the shaft is oriented on the splines let me know.

 

Here is the exact same angle picture of my current setup. You can see the molding of the rubber on the aftermarket is not the same as factory. Right where it should have reinforcement it does not.

 

And here is a picture of the biggest crack that had me worried.

 

And here is the bushing I put in 5 months ago:

 

Nope. I was talking about (my theory, not a solid conclusion) only the rear shaft from the brake drum / txfer case rear output shaft to the roto / diff pinion flange. My wild theory is that in a way the two (fore and aft) flanges may, during rotation, when properly aligned / oriented in relation to each other, either cancel each other out (smooth rotation) or could be unbalanced (noticable vibrations) due to centrifugal forces. If two oposing flange lobes are in alignment with each other then their combined weight at high rotational speed would cause an unbalanced rotation...

If you look at the front prop shaft ( WM section 45, "Propshafts", Pg.1 ), it is made with an intentional mis-alignmet between the fore and aft u-joints causing a (as they call it) "Phased" rotation. SO my theory has a basis, I'm just not sure if that is what is truly causing Brad's Bad vibe. <--- that should have been the title of this thread

Brad - That bushing is done... wow, and after only 5 mo's. Now we can all see that saving a few bucks on a cheap part is a waste of time and money. Best to buy genuine where it is the proven best option even if it is a few duckets more.

And this illustrates the need to mark all parts before removal with a center punch or scratch tool.