ReadyToMount

Seems like you have covered it all, but sometimes we become hypersensitive to issues after spending so much time and money to correct something. Looks like alignment figures should not cause issues. When they moved it to 6 degrees of caster, that probably added the vibrations due to pinion angle. I am sure you have done this already. But I always have someone in the Jeep rock the steering wheel back and forth while I lay under and watch all the parts. Typically something gives before the tires start moving. All new parts you should be good. But may have some bolts that don't match the bushing sleeve or the steering has play in the wheel before the Jeep reacts (loose steering box) Lastly most are against them as I am not a fan typically either, but you may consider trying some Control Arm Correction Kits if you don't already them. JKS makes some good ones (we can sell you a set)
Just throwing out a few other ideas. Hope you do get it figured out. I know the annoyance you are describing.

JK_BUB

I had nearly the exact same issue. Replaced many parts and rotated my 37" Cooper STTs many times before finding that I had thrown some weights on all 4 tires. I suggest, as mentioned before, swap tires/wheels with another jeep and see if it goes away. I did and, after having all 4 tires rebalanced, the issue went away.

twofourflinching

I am in same boat. Added TF BJ and jeep wanders everywhere. 800 miles and 150 offroad miles still tight AF.

Biginboca

1/8" toe in and 4.2* castor is about stock spec. When you lift and go to 37's stock specs are not always going to work any more. 5-6* castor is nicer if you can run that high without driveline issues. And some rigs actually do better with 1/4* toe in or even 1/8" toe out. You can't increase height under the axle with a change in tire diameter and change contact patch width (presumably your backspacing and tire width are not same as stock anymore) and expect stock specs are still going to be your best handling specs.

Also synergy ball joints can take a while (up to 1k miles) to loosen up and break in that may be why you aren't getting a decent return to center.

If it was my rig I would try 1/8" toe OUT. MTR-K are also shitty tires on road. I've run them and had lots of problems. They didn't balance for crap and had 1 out of round from new it always caused handling issues when on the front.

malamuteman

The ball joints have about 10k miles on them. I have read of one guy saying it took about 11k miles to break in but I feel confident that they are broken in or are simply broken.

I did end up removing the 4" springs this weekend and replacing them with 3". The TF springs do add more than 4". In fact I got a measurement of about 1.5" difference. It does ride a little better. I did adjust all the CA measuring angles before and after. Adjusting to exact angles before as these were set by the alignment shop. Please don't blast me I know it will still need to go to an alignment shop. I just wanted to get close to see it made a difference.

However I was/am still getting some weird steering. Today I decided to rotate the tires. Even though this is something I've done once before during this problem I figured it didn't cost me anything and could be the last of the problems. While rotating I took a close look. I did notice some weird almost cupping of the tread. The outside big lugs had a convex curve to it as the middle tread had a minor concave wear pattern. As my girlfriend wanted to drive her car during errands today I only have a couple miles and unsure if the rotation has had any effect. I am getting some local guys coming out to tell me they have had wobble issues and wear issues with the MTR's. I'm hoping I'm not one of them. The rear tires seem to be wearing fairly normal. I'm going to assume/hope for now that this weird wear pattern is due to all the other little issues that I've faced.

malamuteman

Thank you for all the critical thinking and helpful suggestions.