another vibe thread, sick and tired of vibes, i really have no idea anymore

started off with no vibes ....did some add a leafs + shims, got vibes pulled em off, tried boomerang shackles+ shims, got vibes and pulled em. okay, so ive got some major vibes still, from 55+, but only under heavy acceleration, mostly going uphill the t case and pinion angles are both at 6* via t case drop. i pulled the drop at one point with 4* steel shims to even out the angles perfectly with pinion 1* below tcaseoutput, got really bad vibes, maybe ds angle was too steep, who knows, put the drop back on, went back to alright. also swapped in new pass side motor mount, maybe i should do driver side as well? swapped in new tranny mount. retubed and balanced ds with brand new u joints. yj slip yoke. pulled front shaft , still got vibes. went down to 31's and they are supposedly perfectly balanced as well. still vibes new pass side hub assembly too, no play at all in driver side. brand new zj tie rod. still vibes
okay, so im sick of dumping money into the vibe situation, i would have rather bought the dana 60 rear/44 front combo i wanted, so im really trying to pin point these vibes better?

my question is this:
could bad contorl arm bushings cause vibes maybe?
could axle shaft u joints cause vibes?
even with a new tie rod, could a bad tie rod ends on the drag link cause vibes?
could bad leaf sprng bushings cause vibes?
could bad axle wrap cause this and maybe i need to shim like 1 or 2*???

im planning on 95 wrangler 297 disco shafts soon, and doing the control arm bushings, along with the drag link after that, but is there anything else. there was a thread that i cant find that gave info on vibes on accel vs deccel etc , so what do vibes under heavy accel mean, undershimmed, maybe ill throw a 1 or 2* shim under the rear pack and see if that works too.

does any body have any other ideas of what i should also replace, is there anything i overlooked??? im gonna do a sye soon, but i dont think it will fix the vibes since i just recently got them. is

blondejoncherokee said:

my question is this:
could bad contorl arm bushings cause vibes maybe?
could axle shaft u joints cause vibes?
even with a new tie rod, could a bad tie rod ends on the drag link cause vibes?
could bad leaf sprng bushings cause vibes?
could bad axle wrap cause this and maybe i need to shim like 1 or 2*???

Click to expand...

Yes.....but....

blondejoncherokee said:

does any body have any other ideas of what i should also replace, is there anything i overlooked??? im gonna do a sye soon, but i dont think it will fix the vibes since i just recently got them. is

Click to expand...

Reading your first sentence, is sounds like you only got the vibes once you started to lift it more? If so, a SYE will likely be your solution. How much lift are you after? Some XJs are VERY picky.

I assume you installed new U-joints when you re-installed the DS???

Originally Posted by blondejoncherokee
im gonna do a sye soon, but i dont think it will fix the vibes since i just recently got them.

Click to expand...

I see a slip Yoke eliminator in your future!

I would ditch the TC drop & install a SYE & CV shaft, Then shim the rear axle as needed (Probably 3-4 deg or so).

You need an SYE. Even if you do go with a d60-d44 combo, you will still get vibes, and still need an SYE. It's all about the driveshaft angles.

my question is this:
could bad contorl arm bushings cause vibes maybe?
could axle shaft u joints cause vibes?
even with a new tie rod, could a bad tie rod ends on the drag link cause vibes?
could bad leaf sprng bushings cause vibes?
could bad axle wrap cause this and maybe i need to shim like 1 or 2*???

Click to expand...

Yes.
Yes.
Maybe.
Probably not.
If you are at 6* then you shouldn't be experincing axle wrap.

Replace your bushings and DS u-joints. I run at 4.5" with no vibes. But every every XJ is different. Even if you plan on an SYE, if the above needs replacing, replace it.

How's your toe-in?

i appreciate all the help guys.
the ds joints are all new.
about to order control arm bushings too
gonna swap in the 297x shafts with new u joints as soon as i get em.
ill go get an alignment soon too, i thought i did an alright job on the toe in, maybe not...

SYE and CV driveshaft properly shimmed should solve your problem. As stated before XJ's are very picky about driveshaft angles some never need SYE's but most do. If you have the 8.25 rear it is especialy picky and almost always needs an SYE when lifted even 2 inches.

ive got the 44 rear, just swapped in last month...and its in my sig, but i rarely read em myself. im 100% down to swap in a sye, i have front shaft waiting, its more of the extra 200$ right now after spending all that cash on the rest of the stuff ive done in the last month seems like too much right now i think i might just fork out the cash and do it though, i have some 4* steel shims sitting around, and i was thinking about doing some shackles too to help the pinion point up so maybe i wont need shackles, plus shackles are easier than shims to install, ive done both at least 7 times on my jeep in the past 3 months trying to fix the vibes for "cheap" so much for cheap, its cost me more than sye would have!

Have you tried driving the jeep with the front drive shaft removed? I had the same problem ended up being the front.

yah pulled the front praying that was it. still vibes. just as bad too. is it possible that too much/not enough "toe in" or other alignment issues could cause vibes? i ordered new lca bushings and a band aid ie new steering stabilizer on the way. then after that the axle shaft u joints after i get the 297x shafts and maybe the other hub too. soon enough that porc sye will be in my garage if all of this doesnt fix it....

Quit being a CAB and do it the right way and be done with it.X10 the benifits and you'll never look back.

This may not be your problem, but it happened to be mine. What happened to mine was that I had "tweaked" the output shaft from the T-case, and didn't know it.

What I mean by tweaked is that at some point while I was wheeling I must have been trying to get up some ledge or something and I must have come back down in such a way that it created trmendous force on the output shaft, which tweaked or bent it and made it no longer rotate in perfect symmetry. Instead it spun like a lopsided basketball, which caused the vehicle to vibrate even though my angles were good and my drivelines and everything was balanced and good to go. I don't know if I described that well enough or not.

It may be one place to look, if you haven't already.

dude the output shaft is a damn good idea. i think in all of my trying to charge through this i didnt even think about it, well im planning on doing a sye after all of this so maybe i should wait until then?...
i recently have done the lca bushings(rubber at frame, poly at axle) new motor mounts, another new zj tie rod(1st one was used for 15$, this one is new) pass side hub bearing, jks quicker discos and jsut ordered a new stock track bar, some 297 shafts and gonna swap in new u joints, leaf bushings, tre end at pitman arm, stock uca's with bushings, pass side hub, new crossmember, another new tranny mount instead of another used one, and of course i have been rechecking the alignment everytime. after i get done with this ill go to a sye if it stil vibes.

ok decided to go sye(porc) as next on the list and then if still vibes ill do the other stuff listed cuz that will all cost more than the sye. i have some 2" lift shackles waiting for when i do the sye, has anyone ran 2" lift shackles with a sye on 3.25" rear lift and had to shim? im hoping i wont have to shim anything if i throw the shackles on i hope it points the pinion to be 2-3 degrees below the driveshaft angle to account for axle wrap from my old saggy rustys 3.5" lift springs. i do have some 4* RE steel shims lying aound
ill probablly do the spring bushings at that point too...so basically who was around 3" of lift with a sye?

Ideally you want to shoot for the pinion 1 degree below driveshaft angle. 2 to 3 degree's is alot and will most likely cause vibes at freeway speeds. Unfortunately there is no magic formula to tell you what will eliminate vibes, its trial and error until you find the sweet spot.

jeepme said:

Ideally you want to shoot for the pinion 1 degree below driveshaft angle. 2 to 3 degree's is alot and will most likely cause vibes at freeway speeds. Unfortunately there is no magic formula to tell you what will eliminate vibes, its trial and error until you find the sweet spot.

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Everyone always says that but it seems that in practice it's nearly impossible to achieve. In the front I would have to go with 0 deg caster to achieve that 1 degree, and in the rear I'd need probably 8 deg shims which would wrap up my shock mounts a bit. I have a 4.5" lift.

I'm running an SYE with a front DS on the rear I'm at 14 deg DS angle and about 7 deg pinion with 3 deg shims. The front numbers are different but about the same difference about 7 deg pinion to DS. I have no vibes anymore but really don't see how those numbers could be reached without some cutting and welding of shock mounts, spring perches, inner c's or something.

2-3* down at the pinion end of the shaft is best to deal with inevitable "axle wrap".
With a double-Cardin joint style shaft, a minimum of 1* down is needed to keep from burning up the pinion u-joint, = another 1 to 2 for axle wrap, unless you have a traction bar on the rear axle, or have a linked rear.

At 3 inches of lift unless he is using blocks in back there should not be any axle rap or very minimal. Like I said before its just trial and error, what works for some may not work for others. If you go to Tom Woods web site there is a good article about all of this that will help. I found that with a combination of longer shackles and shims you should be able to find the correct angle. I am at 6" of lift in back and run a 4* shim with 1 1/2 in lift shackles and a SYE, of course, and my pinion is 1 1/2* below the DS angle with no vibes.

thank you guys for all the help. ive been thoroughly researching vibe threads for months now and tried a ton of diff. t case drop and axle shim combos along with diff axle shim combos with different shims as well. i was just wondering basically at this point if i can get away with just a longer shackle to "shim" and point the pinion up towards the t case cuz im sick of swapping in degree shims. but honestly i wont know until i install the PORC sye and the rough country 1.5"-2" lift shackles. i will post up once i get the sye in and the shackles on what the angles are and like i said i have steel shims lying around now...i was originally trying to avoid the "cost" of a sye but after all the stupid money i put into shims and steel for drops and shackels and add a leafs and new driveshafts and junk i shoulda done the sye in the first place. i highly reccamend to anyone to just fork up the 200$ for the sye and be done with it instead of dealing with countless weekends of tearing apart the rear leaf packs on sundays to mess with angles and shims... anyone running a porc sye and 3" leaves with 2" shackles? if so what shims if any are you using on your leaves?

ratcat said:

Everyone always says that but it seems that in practice it's nearly impossible to achieve. In the front I would have to go with 0 deg caster to achieve that 1 degree, and in the rear I'd need probably 8 deg shims which would wrap up my shock mounts a bit. I have a 4.5" lift.

I'm running an SYE with a front DS on the rear I'm at 14 deg DS angle and about 7 deg pinion with 3 deg shims. The front numbers are different but about the same difference about 7 deg pinion to DS. I have no vibes anymore but really don't see how those numbers could be reached without some cutting and welding of shock mounts, spring perches, inner c's or something.

Click to expand...

Front is nowhere near as important as rear. you dont get axle wrap with coil springs. In the front its about finding that happy medium between caster and your pinion angle. you dont follow the same rules as you do for the rear (where you want your pinion angle 1-2 degrees lower than your DS angle).