Vibration at 70 mph

[Thunderhead]

Do you have adjustable control arms and cv rear drive shaft?
I run a 4 " lift with 5.5 degrees of caster and have no vibes in the front. With a 3" lift you could probably run 5.5-6.0 degrees of caster and be fine.
Your running 2.9-3.2 degrees which is going to pitch your front pinion angle too high. which could cause some vibes.
You can get you rear thrust angle in with and adjustable rear track bar, and even though the rear toe is not adjustable on jeeps, you could get it within spec with adjustable control arms in the rear. Basically your rear axle is not squared up in the rear.
You will also want to check your rear pinion angle.


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