I installed a SYE after my 2" lift in my 99 XJ and im running a front 98 D/S in rear.At first no vibes for 2 months. Then the vibes started,so after some research i installed 3* shims to correct pinion angle. Vibes are still there. So, i removed front d/s and this quited vibes some,but they are still in rear from 50 to 65 mph.I thought i could have caused some u joint damage before installing shims. So i will have the 98 d/s balanced and checked , and will install in rear to see if this corrects vibes. Can i do anything else to correct problem ? Could pinion bearing be bad?

 

with an SYE you do not need a shim the pinion angle for an SYE needs to look as follows:



I am willing to bet your angles are off.

 

I thought pinion angle needed to point to out put shaft for a sye and double cardan.

 

its early. I missed the SYE part and i even read it

what you need to do is get an angle finder on the pinion and he DS.

3* MAY be to much or to little even 1* off and it will throw it out of wack.

the pinion bearings you can check by just feeling if they are loose, if they are not loose you are fine

 

Shouldn't use a front ds in the rear til 4.5" and up

 

I researched the sites and most said you could use it. What should i be running?

 

how do the joints look

 

Terrible advice.
Front DS's are what 95% of people use with an SYE. There's a slip joint that allows it to extend/compress as needed. What else do you suggest he use??

OP, what made you decide to go with 3* shims? If you didn't check, I'd suggest measuring all of your rear driveline angles. It's possible you may need shims, but knowing the exact angles is going to let you know the exact degree that you need.

 

my mechanic said they seem tight

 

Found your problem

 

I know there is a slip joint in them. Just saying it's usually something else with a 3" lift with the vibs

 

That still makes no sense. Vibes can come after a 2" BB, or be non-existent at 6".

Like I said though, what else do you suggest him to use besides the front DS??

 

Check his joints or a tc drop. He has done different things that usually fix it but still have problems so it's prob something else and is off a little bit. What it is I don't know. The ds could not be balanced right.

 

Maybe I need to reread the post again, but he said he removed the rear driveline and he still has vibes. So I would now look at the front driveline. If the CV needs to be rebuilt or a ujoint is bad and drive line is turning, then this will cause vibes too.

On a related note, the CV shaft and STE can be put on amy amount of lift. But it needs to be set up properly afterwards. I have seen several vehicles with bad driveline vibes because they were not set up properly afterwards. Here is the procedure for both types of shafts.

http://www.xjtalk.com/showthread.php?t=7299