Shimmy at 65mph in a 2006 LJ

[catbones2010]

Per previous post, I've spent the last two months chasing a shimmy. Some say it's vibrations, some say shimmy. With everything I've done and replaced, I'm at a point where removing the rear driveshaft or putting it in 4H eliminates the vibrations.

Some suggest SYE and new driveshaft but that sounds extreme since I shouldn't need it until I'm over 3.5 lift on an LJ. However, I've rear some with 2" lift had vibrations and they did the 1" MML.

Thoughts??

 

[06lj]

If removing the rear shaft eliminates the vibrations then you have identified the cause. Did you have the lift and vibrations before your regear?
I put 5.13's in my 06 LJ and have vibes over 60mph that are coming from the rear shaft. I have an SYE and DC driveshaft. I expected issues with the front axle as that's what most people have reported. For whatever reason my front axle is vibration free. I've done every adjustment possible so I've concluded that the driveshaft RPM's are just to high for the rear shaft.

 

[catbones2010]

If removing the rear shaft eliminates the vibrations then you have identified the cause. Did you have the lift and vibrations before your regear?
I put 5.13's in my 06 LJ and have vibes over 60mph that are coming from the rear shaft. I have an SYE and DC driveshaft. I expected issues with the front axle as that's what most people have reported. For whatever reason my front axle is vibration free. I've done every adjustment possible so I've concluded that the driveshaft RPM's are just to high for the rear shaft.

Where'd you get the rear from? Didn't they balanced your DS for higher rpms?

So SYE and DS didn't fix it for you.

To answer your question, no vibes and no shimmy for 2 years with 5.13s in. They all of the sudden showed up and at first it was like a shimmy... steering moving left to right while your holding it. Some said might be caster vs front ds. So the weird thing was that when I did make adjustment to go from 6.3 caster to 7, the vibe/shimmy moved to lower speed. If I gave less, it went to higher speed.

Having that i start to investigate things and saw slight movement in the front trackbar and replace bushings, nothing. Replaced the trackbar with another, still there. Took front driveshaft out, still but more defined.

Then went down the hole of replacing and chasing this which came to ball joints and the lower ball joint I could wiggle. So replaced ball joints, while I was there replaced axle shaft ujoint and hubs. The shimmy still there.

Some kept insisting tires balance. Even thought over the past two months chasing this i also did balancing 17 times 5 or 6 different shops. Still nothing.

Someone said, take rear driveshaft out. I took the rear out and the shimmy is gone, the vibes are there but I can live with those. The shimmy is annoying lol.

Went back to the shop that did the alignment and was told that they do it based on stock settings as they can't just adjust it per specs manually entered. Ok so I'm not aligned. But I can see caster is around 6-7 and I can flip flop it to make this shimmy happen higher in speed or lower.

So at this point I've got an appointment to get the alignment done.

Someone said I should try to do 5 caster driver and 5.6 passenger as 7 is ideal for stock and you need less of it with a lift so 5 with 2" lift would be good.

That's where I stand right now. Annoyed. Lol

 

[06lj]

Where'd you get the rear from? Didn't they balanced your DS for higher rpms?

So SYE and DS didn't fix it for you.

To answer your question, no vibes and no shimmy for 2 years with 5.13s in. They all of the sudden showed up and at first it was like a shimmy... steering moving left to right while your holding it. Some said might be caster vs front ds. So the weird thing was that when I did make adjustment to go from 6.3 caster to 7, the vibe/shimmy moved to lower speed. If I gave less, it went to higher speed.

Having that i start to investigate things and saw slight movement in the front trackbar and replace bushings, nothing. Replaced the trackbar with another, still there. Took front driveshaft out, still but more defined.

Then went down the hole of replacing and chasing this which came to ball joints and the lower ball joint I could wiggle. So replaced ball joints, while I was there replaced axle shaft ujoint and hubs. The shimmy still there.

Some kept insisting tires balance. Even thought over the past two months chasing this i also did balancing 17 times 5 or 6 different shops. Still nothing.

Someone said, take rear driveshaft out. I took the rear out and the shimmy is gone, the vibes are there but I can live with those. The shimmy is annoying lol.

Went back to the shop that did the alignment and was told that they do it based on stock settings as they can't just adjust it per specs manually entered. Ok so I'm not aligned. But I can see caster is around 6-7 and I can flip flop it to make this shimmy happen higher in speed or lower.

So at this point I've got an appointment to get the alignment done.

Someone said I should try to do 5 caster driver and 5.6 passenger as 7 is ideal for stock and you need less of it with a lift so 5 with 2" lift would be good.

That's where I stand right now. Annoyed. Lol

I retract my previous conclusion of the rear driveshaft. I was imagining vibrations vs a shimmy. Running in 4h with or without the rear driveshaft is putting the same load on the front axle and eliminating the symptoms. The load would be increased in the upper control arms. During your front end rebuild did you replace your upper control arm bushings? That's my only thought as it seems you have done every obvious repair. Hopefully you can find an answer.

The rear shaft I have is a Rough Country. I know and I'm not proud. I got it with a bunch of other parts a long time ago so at least I didn't pay much for it. It was new and sat in the garage for years until I went to a larger lift and needed an SYE. To it's credit it did run fine with the stock gearing. I considered getting it balanced but am just planning on replacing it with a quality shaft early next year.

 

[catbones2010]

I retract my previous conclusion of the rear driveshaft. I was imagining vibrations vs a shimmy. Running in 4h with or without the rear driveshaft is putting the same load on the front axle and eliminating the symptoms. The load would be increased in the upper control arms. During your front end rebuild did you replace your upper control arm bushings? That's my only thought as it seems you have done every obvious repair. Hopefully you can find an answer.

The rear shaft I have is a Rough Country. I know and I'm not proud. I got it with a bunch of other parts a long time ago so at least I didn't pay much for it. It was new and sat in the garage for years until I went to a larger lift and needed an SYE. To it's credit it did run fine with the stock gearing. I considered getting it balanced but am just planning on replacing it with a quality shaft early next year.

Ohh no problem. I'm just driving myself crazy trying to figure this out. I'm sure my front and rear driveshaft isn't handling the 5.13 gears r8ght being they are both stock still with new ujoints in them. I was thinking maybe it's the front one since shimmy usually is up front issue with ball joints or some steering component gone. But taki g the front off and it still being there what confused me. Then after part replacement, taking rear out and it being fine is another confusion. I don't mind dropping $700 for new driveshafts as this LJ is a baby of the three and with 68k on it only.

That said it does have aftermarket parts, so all control arms are core4x4. I did look into the bushings and while there is side to side play between the bushing and the control arm. I think there should be a little bit. Lower ones don't have any play approaching that same test with a prybar and moving it between the bracket of the frame and the bushing. How much is too much, i don't know. That said, I can't remember if I did change the bushing in the axle for the uppers. I can look and get some, replace them.

Honestly right now I think I should figure out what my caster is vs driveshaft angle up front and what separation between rear and front axle is. And that's because while I did have the lift put in by a shop with the control arms they didn't use my provide to them at the time cam bolt deletes. So they left the factory adjustable cams in there with adjustment. While I was investigating the issue of shimmy, I got annoyed that those were there and removed them and put the cam deletes hoping I'd have alignment done the next day, but they over booked and now I'm scheduled for Dec. 3rd. For alignment with using control arms to adjust caster angles but knowing me I might try and figure that caster all myself and set it at about 5 degrees with 2" lift and 33 tires. 7 is factory with no lift and 33s.

 

[John Cooper]

What brand lift are you running? Upper and lower control arms?

 

[John Cooper]

Ohh no problem. I'm just driving myself crazy trying to figure this out. I'm sure my front and rear driveshaft isn't handling the 5.13 gears r8ght being they are both stock still with new ujoints in them. I was thinking maybe it's the front one since shimmy usually is up front issue with ball joints or some steering component gone. But taki g the front off and it still being there what confused me. Then after part replacement, taking rear out and it being fine is another confusion. I don't mind dropping $700 for new driveshafts as this LJ is a baby of the three and with 68k on it only.

That said it does have aftermarket parts, so all control arms are core4x4. I did look into the bushings and while there is side to side play between the bushing and the control arm. I think there should be a little bit. Lower ones don't have any play approaching that same test with a prybar and moving it between the bracket of the frame and the bushing. How much is too much, i don't know. That said, I can't remember if I did change the bushing in the axle for the uppers. I can look and get some, replace them.

Honestly right now I think I should figure out what my caster is vs driveshaft angle up front and what separation between rear and front axle is. And that's because while I did have the lift put in by a shop with the control arms they didn't use my provide to them at the time cam bolt deletes. So they left the factory adjustable cams in there with adjustment. While I was investigating the issue of shimmy, I got annoyed that those were there and removed them and put the cam deletes hoping I'd have alignment done the next day, but they over booked and now I'm scheduled for Dec. 3rd. For alignment with using control arms to adjust caster angles but knowing me I might try and figure that caster all myself and set it at about 5 degrees with 2" lift and 33 tires. 7 is factory with no lift and 33s.

What core arms do you have?? JJ joint or regular bushings?

 

[catbones2010]

What core arms do you have?? JJ joint or regular bushings?

Core4x4 and regular bushings but the ones on the axle is believe are still stock.

Here's the amount of movement I've got. I think that's normal on this side but the axle side is the same amount with old bushings. I think those did get replaced.

https://photos.app.goo.gl/XcPd7w7fCjCF4dLJ7

 

[John Cooper]

Core4x4 and regular bushings but the ones on the axle is believe are still stock.

Here's the amount of movement I've got. I think that's normal on this side but the axle side is the same amount with old bushings. I think those did get replaced.

https://photos.app.goo.gl/XcPd7w7fCjCF4dLJ7

I don't believe you should have any side to side movement.

Are your bolts torqued down correctly?

 

[catbones2010]

I don't believe you should have any side to side movement.

Are your bolts torqued down correctly?

I'll recheck but I would believe so.

 

[catbones2010]

I don't believe you should have any side to side movement.

Are your bolts torqued down correctly?

I'll recheck but I would

I don't believe you should have any side to side movement.

Are your bolts torqued down correctly?

I might reach out to core4x4 and see. Bottom ones I can't move no matter what I do. But good to see and eliminate it.

 

[John Cooper]

I'll recheck but I would


I might reach out to core4x4 and see. Bottom ones I can't move no matter what I do. But good to see and eliminate it.

I would retorque uppers and lowers.

Never hurts to be on the safe side.

 

[catbones2010]

I would retorque uppers and lowers.

Never hurts to be on the safe side.

Will see what Core4x4 says but yeah I'll retorted them and get new bushings for the axle side plus hardware. The hardware seems to be stock.

 

[catbones2010]

I would retorque uppers and lowers.

Never hurts to be on the safe side.

What do you like for bushings? The regular rubber stuff or poly?

BTW if it's rear driveshaft, IF, you think MML 1" might work without SYE? I honestly don't think I need SYE.

 

[John Cooper]

What do you like for bushings? The regular rubber stuff or poly?

BTW if it's rear driveshaft, IF, you think MML 1" might work without SYE? I honestly don't think I need SYE.

I would only run rubber bushings, i had 2 different RC 4" lifts on jeeps and both were poly bushings.

They squeaked like crazy. When they wore down they made the Jeep drive squirrely.

I haven't ran a SYE or a MML.

What size lift do you have now.

 

[catbones2010]

I would only run rubber bushings, i had 2 different RC 4" lifts on jeeps and both were poly bushings.

They squeaked like crazy. When they wore down they made the Jeep drive squirrely.

I haven't ran a SYE or a MML.

What size lift do you have now.

2" on my LJ with 33s ... nothing major from stock

 

[John Cooper]

2" on my LJ with 33s ... nothing major from stock

If you go with a MML, I would use the aluminum blocks that go under the stock mounts.

 

[catbones2010]

If you go with a MML, I would use the aluminum blocks that go under the stock mounts.

Appreciate the help and info. I will replace the axle UCA bushings and see what core4x4 says plus retorque stuff as I wait and let you know how that works out.

Would be nice to get that stable ride at 65 to work.

 

[John Cooper]

Appreciate the help and info. I will replace the axle UCA bushings and see what core4x4 says plus retorque stuff as I wait and let you know how that works out.

Would be nice to get that stable ride at 65 to work.

@AndyG can maybe chime in also.

He helped me a lot on my last Jeep, before I got my Rubicon.

 

[catbones2010]

@AndyG can maybe chime in also.

He helped me a lot on my last Jeep, before I got my Rubicon.

That be awesome as well. Any idea what the hardware size is for stock on those UCA axles? The current ones stock don't look so healthy.