BuddhaJeeper

So after installing my lift (@4.5 Zone) and sye my XJ is still experiencing some significant vibes once you hit 50+ mph.

So far I have done the following:
1. Shim the rear pinion angle. 4x4 shop installed a 6* shim
2. Sye and Adam's rear custom shaft
3. New ZJ tie rod upgrade. (All brand new parts)
4. New steering stabilizer
5. Rebuilt front driveshaft (Spicer)
6. New axle shaft u joints (Spicer)
7. New unit bearings (Timkens)
8. News front brakes (new pads, rotors and extended brake lines)
9. Rear Disc conversion (new pads, rotors, extended brake lines, national bearings and seals)
10. HP Dana 30 swap
11. Adjustable upper and lower control arms
12. New Motor Mounts ( Brown Dog rubber) and transmission mount
13. Changed both diff fluid
14. Transmission fluid
15. Alignment
16. Rotated and balanced wheels and tires
17. Changed Transfer Case fluid
18. New track bar and bracket ( IRO Double Shear)

I've also re torqued all my bolts, checked the gears when I had both diff covers off and checked for play at all 4 yoke locations. Everything seemed to look ok to me. So basically I'm at my wits end.

Do you guys have any idea what I might be missing or a clue as what it could be? Only other thing is to take to another 4x4 shop and have them give it a once over

andrewmp6

Was the Alignment done before or after the trackbar and tie rod ends ?And have you tried rotating the wheels ?And do you have a steering box brace ?

BuddhaJeeper

I do not have a steering box but the alignment was done after the new steering and track bar install. Just had the tires and wheels rotated and balanced today.

Should have added in my first post that I installed new Spicer ball joints.

andrewmp6

Only ideas i have is the steering box is flexing or maybe a warped rotor.

peligro113

What were the measurements before and after the alignment? What are your rear pinion, transfer case, and driveshaft angles?

BuddhaJeeper

@andrew...well the rotors are brand new so I think its unlikely they are warped although I could have gotten a bad one from the parts store. I was planning on getting a steering box brace in the future. I may move that higher on the priority list.

@peligro...what measurements are you referring to? i had a 4x4 shop check the rear pinion angle and install the 6* shim. So I'm not sure what the exact angles were.

I have a long weekend so I was planning on doing some more "noggin pokin" this weekend.

Jeepin'_Aint_EZ

Is the vibration consistent at 50mph or is it only there while accelerating? Just looking for more specifics on the vibration you're experiencing. Can you notice it in the steering wheel? Can you feel it in the brakes? Things like that.

BuddhaJeeper

Yes once I hit the 50 mph mark its constant. It eases off a little when I let off the gas pedal but still very much there. At 60+ mph it starts causing the mirrors to go blurry and a lot of the interior trim buzzes or rattles. I stick to under 55 mph when I do drive it.

I don't feel it in the steering or brakes. I feel it more coming from the body of the jeep like under my butt and feet if that makes sense.

Jeepin'_Aint_EZ

That kind of high speed vibration is usually a balancing issue.

BuddhaJeeper

As in tire balancing? That would be a easy enough of fix. I'm looking to get new tires and wheels anyway.

Jeepin'_Aint_EZ

Tires, drive shafts, brakes drums/rotors, etc. Anything that needs balancing lol. If you don't feel it in your steering wheel or brake pedal most likely not your tires.

BuddhaJeeper

Well the DS is brand new from Adam's as well as front and rear brakes. I'll give everything a once over tomorrow and see if I can find anything unusual. Could be a bad install on my part seeing as I'm relative new to Jeeping.

Thanks for the tips so far guys.

Cane

pinion angle in the front maybe? i current have vibes in the front caused by either a loose front yoke on the transfer case, or the output bearing is going bad. and since i'm on stock uppers and fixed lowers, my pinion angle isn't the best which I'm thinking might cause the vibe at highway speed. this makes all the pennies and screws that lay in my center console to do a lot of noise.

did you try disconnecting the front driveshaft, driving around in 2wd, see if that makes a difference? if it doesn't, reinstall the front DS and remove the rear, drive around in 4HI and check again if the vibe is still there or not.

BuddhaJeeper

I was planning on taking the front DS off tomorrow and driving it around. Take the wheels off and check the brakes and rotors too.

I'll check the rear DS as well.

Thanks for the tip Cane.

AZ89Laredo

I had this exact problem about 2 weeks ago. When they installed the sye did they check your U joints? that was what was causing my vibrations I had a completely shot u-joint that was actually so bad that it cracked the yoke.