Just fixed driveline vibration!!!For free!

oh g'damn! that is not reasuring since I have a similar issue as you and I'll be doing mine this weekend

 

Ya not sure whats going on. Was super confident this would work. I feel I've tried everything. If you take this on, make sure your U bolt threads are nice and clean from dirt etc. You can cause big problems when removing the nuts if you don't.

 

i have a theory, as i am getting ready to install the 2" AAL myself and i am clearly going to have some issues- is it possible the 2" AAL is causing Wrapping of the leaf pack?

ie: at rest its at 3.5* off but get on the gas and its "torquing" it to ~0*?

if im right, that would explain why it got worse when you shimmed it back to 0* because now your going to a -3.5*. Food for thought....

 

Darn I thought that would work per the Spicer docs. You say it brought the pinion down to zero? But what was the angle on the U joint at the pinion before / after the shim? You had no vibes before the lift right? This and the front end vibe on lifted 4x4's is why some have gone back to stock! It's not that bad for me I've kind of gotten used to it but would be nice to be free of these annoyances! Right now I have no shims whatsoever.

 

Pinion was down to zero. My Diff pinion U Joint was 6.5* after shim and 3.1* before.

My angles with no shims or spacers are: TC 0:First shaft 4.9* Second Shaft 6.1*: Diff Pinion 3.1*/ First Joint 4.9*: Second Joint 1.2*: Third Joint 3*.

Right now I have shimmed CB 1/4 to straighten out the first and second shaft and this is pretty much the same amount of shudder that I have noticed with all the different combination of shims and spacers except when I put the 3* axle shim thick fwd which had the worst results.

I'm curious if this has anything to do with the Transmission TSB for the aft mount. My trucks VIN does qualify for it. I'm a lot more aware of vibes and sounds ever since the lift because of the problems know to occur, so there is a slight chance it was there before. Is the new Tran mount more heavy duty?? I also changed my rear LSD fluid with Royal Purple at the same time as the lift. Could it be the clutch pack slipping/shuddering. I thought that was only felt when turning...

Oh and yes I do have the front diff bearing problem too and I am in the process of getting a new axle and a modified bushing from East Coast Gear Supply to cure that issue.

 

Those #'s are very close to what I have. U joints angles from TC to Pinion: 5*,0.8*(no CB shim), 2.5*. Thats why I thought getting the Pinion to 5 or so should've done the trick - I was going to try a 2* axel shim backwards. From your results I dont think I'm going to F*k with it anymore unless King Moo goes with a new leaf pack and that cures it. Or I may try removing the 3aal and bringing the rear back to stock temporarily to see. Too much other priorities for me now though. As far as the front end I'm dying to hear your results with the ECGS bushing. Please post or PM me after doing that. Thanks and good work.

 

I'm doing it this weekend. Bought my 3.5* shims today and I plan to install them fat side forward to bring the pinion down.

my angles (zeroed at TC):
front shaft: 3.5*
rear shaft: 4.8*
pinion: 3.7*

 

I feel by putting the 3* axle shim in thick fwd caused way to much angle at the pinion giving me my outcome. If I had the chance I would rather remove the AAL and go for a drive to be sure the vibe is gone and remeasure stock angles. This would give me a base line and would also be able to see if and how much the pinion rotates when lifted.

Another thing I discovered today is that when I put my truck in 4WD and accelerated from a stop it was smooth as glass. I did this a few times with no vibe at all. This could mean A) pinion dose not torque up as much when starting up in 4WD and angles don't get to the point of vibration or B) My front Diff bearing that causes vibes/hums at higher speeds is also felt when accelerating from a stop. It would be great if someone else could try this, especially if you know you have a front Diff bearing prob.

HB Taco- How much lift do you have front and back? We seem to have very similar set-ups and issues

 

Same for me I wish I could leave it in 4wd all the time. All vibes disappear. I think the rear take off shutter goes away in 4wd because a lot of the torque is shifted to the front. Some say a traction bar may help - if its a wrap issue. I think that sloppy CB has a lot to do with it.
I have about 2.5" in the front and about 2" in the back. If I empty the bed and take the tonneou off it's about 2.5" in the back.

 

this sucks. I picked up 2 shims today and it turns out they're not identical and one of them is not even closed...

 

You didn't see that when you bought them ?

 

was in a hurry and they were stacked...

 

That sucks

 

WTF! Honestly the angles look the same - one is shorter. If your handy and have the time and resources you could try them? In the end they will accomplish the same thing. I just wouldn't leave them in permanently.

 

They're the same length. My pic is bad. They are not the same width. They are both supposed to be 2.5" but one is a little wider. Regardless, I was planning to shave them down to 2.375.

Now I'm wondering if i should just go ahead and use these. I just don't like the fact that the one doesn't have a closed hole.

 

Does anyone have the OME Dakar leaf pack with no take of shudder? If axle wrap or bad pinion angle is causing this with the 2" AAL maybe a different/better leaf pack would solve this prob...

 

I have the Dakars and have no take off shudder but I do have a vibe at 40-45 mph

 

^^ Usually vibes or shudders around that speed could be caused by a unbalanced tire.. Had it twice on my truck..

 

Ya I know , thanks , but it's the same over two sets and been road forced

 

Could it be your front diff needle bearing? Do you have the same symptoms in 4WD??