Vibration at 50+ MPH

[JoePal]

I wish i could make this shorter, but I need to give background. 06 TJ 4.0 Manual. Several years ago, I did a 2.5“ lift, had a vibration immediately that was 98% resolved with TC drop.
Fast forward a short time ago i needed a throw-out bearing. The mechanic took things apart and found bearings floating around and i needed to replace the flywheel. Did all that work along with clutch and rear main seal.

When i took the TJ back i noticed a new vibration starting at around 50 mph and higher. When i discussed it with that mechanic he said a SYE and a double cardan drive shaft would probably resolve. I’m done with mechanic as $3K was what he quoted.

I removed the rear drive shaft trying to isolate the problem. (thinking the mechanic put the drive shaft back incorrectly and it was out of balance) I thought i drove better but now second guessing myself.

I found a reapable shop that does a ton of jeep work and had the SYE kit and a Adams CV drive shaft installed. I still have the vibration. This shop also told me that the balancer was loose.
This shop now suggests adjustable rear upper control arms but before doing that replace the lowers with OEM, the busking were shot. i replaced with OEM and WOW what a difference in the ride.......... but i still have F’king the vibration.

NOW WHAT? There are vidoes out there that suggest a “dynamic vibration” not a driveline. since the vibration starts at around 50 MH and higher.

I have 120K on this girl but I'm ready to give up. Your thoughts?
TIA

Joe

 

[macleanflood]

Pictures would help.

I would assume the SYE removed the balancer from the transfer case.

Adjustable upper rear control arms are correct to get the right pinion angle. You'll probably also need an angled track bar bracket. If your lowers are shot, well, that's why the shop wants to replace them.

And depending on what you want to do you might be better off with a full set of control arms from Savvy or Core 4x4.

You may also need new track bars to center the axles.

-Mac

 

[JoePal]

thanks Mac. I replaced the rear lowers with OEM. Greatly improved the ride except didnt effect the vibration. Also i replaced the track bars to center the axel a while ago. The shop is recommending JKS adjustable rear uppers. I assume because of the cost. i get some photos up too.

 

[MikenMel]

Have you checked the front DS? We have an '04 TJ with a 3 1/2" lift. It developed a vibration that I could feel most beneath my seat that was between 50 and 60 mph. It took me a while to hunt it down, but it ended up being the front DS. I could move the slip yoke about an 1/8th inch in any direction. It turned out that the lift had extended the stock DS to the limits and the internal splines began wear down. I replaced it with a custom length DS, and the problem went away.

 

[JoePal]

thanks, i have adams drive shaft that was installed when my transfer case was rebuilt 2 years ago. i know the machanic gave adams the measuments per their instructions.

 

[JoePal]

couldnt get the angle off the TC or the pinon tonight. i'll try tomorrow.