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-   -   driveline vibs with SYE and cv shaft (http://www.wranglerforum.com/f210/driveline-vibs-with-sye-and-cv-shaft-39494.html)

willysmb 11-08-2009 06:34 PM

driveline vibs with SYE and cv shaft
 
Did some tweaking on my new RE superflex/SYE/tom wood driveshaft.Set the toe as per Jerry Bransford,adjusted the drag link to get the steering wheel lined up.Shortened up the front UCA,s to add a little pos caster.One highway test drive later,I still have vibs.Everything else is great,high speed bumps,no issue,tracks nice,but has vibs it never had, even with the old driveshaft.I put back the 3 7/8ths washers I was using as a transfer case drop,1/2 inch total under each bolt.Completely solved the vibs.Prior to this I did try 2 rear drive shaft angles measured between the shaft and diff pinion.First one was straight,the other was 2 degs low at pinion.Is it possible I dont have the angles set right? or do I need both the SYE and transfer drop? My setup is a RE 3.5 superflex with 3/4 poly spacers on top,so its closer to the 4.5 RE kit.I also have a JKS 1 1/4 BL/1" MML.Im OK with a small transfer case drop,but I thought it wasnt needed with the SYE?

nicolas-eric 11-08-2009 07:06 PM

Do you have some pics of your front/rear DS angles?

I have 5.5" of lift and a 3.5" belly-up TC skid. With the SYE and CV DS I donīt have any vibes.

Are you sude that the vibes come from the rear DS? Remove the rear DS and drive with the front DS only (TC in 4H). Are the vibes still there or gone?

AzTJ 11-08-2009 08:26 PM

I'd play with the rear pinion angle some more.

willysmb 11-08-2009 08:46 PM

Quote:

Originally Posted by nicolas-eric (Post 482883)
Do you have some pics of your front/rear DS angles?

I have 5.5" of lift and a 3.5" belly-up TC skid. With the SYE and CV DS I donīt have any vibes.

Are you sude that the vibes come from the rear DS? Remove the rear DS and drive with the front DS only (TC in 4H). Are the vibes still there or gone?

Ill see if i can take some pics tomorrow.I was going to remove the rear driveshaft this morning,but i threw my back out.Couldnt climb under the jeep.So I just added the washers back under the trans skid plate. At least I know its related to driveline angle,front or rear.I also noticed on Saturday,that my RE rear trackbar bracket isnt high enough for the springs with the added poly blocks.My rear axle is offset the the right side about 5/8th inch or so.Going for an adjustable rear trackbar.

jdhallissey 11-08-2009 09:54 PM

Drive shafts were are they from?

willysmb 11-09-2009 05:34 AM

Quote:

Originally Posted by jdhallissey (Post 483001)
Drive shafts were are they from?

front is stock,rear is tom wood cv................

jdhallissey 11-09-2009 11:49 AM

sorry just saw the tom woods. Do you feel the vibs in your butt or you hands? As in the vibs coming from the rear or the front? I take it the rear. When are they coming speed wise. How bout is it just a shutter taking off from a light or like at 55mph to 60 kind of thing.

Jerry Bransford 11-09-2009 12:15 PM

This is precisely how your rear pinion angle should be set... directly in line with the rear driveshaft. Ideally, 1-2 degrees under that to help compensate for the TJ's minor axle wrap (which slightly lifts the pinion shaft) during acceleration.

http://www.4xshaft.com/images/cv_angle.gif

Properly set per that illustration from Tom Wood's Custom Driveshafts' site, your rear driveshaft and its u-joints will not vibrate.

nicolas-eric 11-09-2009 12:18 PM

After installing the SYE and CV DS I had an angle of about 7-8 degrees at the pinion and thought that would be ok. But there were still vibes. Now with 1.5 degrees the vibes are gone.

Jerry Bransford 11-09-2009 12:22 PM

Quote:

Originally Posted by nicolas-eric (Post 483462)
After installing the SYE and CV DS I had an angle of about 7-8 degrees at the pinion and thought that would be ok. But there were still vibes. Now with 1.5 degrees the vibes are gone.

The specific angle of the pinion shaft is of no concern so you can't say a specific angle is ok, it only needs to match that of the driveshaft. The taller the lift, the steeper the angle required to keep the pinion angle in line with the CV driveshaft.

nicolas-eric 11-09-2009 12:27 PM

Sorry. I was talkin about the angle between the pinion and the driveshaft.


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