Vibration after lift

holy_crap

holy_crap

Member
Good evening, it's been a while since my last post, I hope,everyone is having a good holiday season.

I gave my son a lift and new tires for Christmas. It is a Rock Krawler 2.0 Stock Mod which basically consists of 4 springs, front adjustable track bar, rear track bar bracket and 2 sway bar disconnects. I also added Billstein shocks. The tires are 33x12.5x15 BFG KO2 on ProComp wheels i think 3.75 back spacing. The Jeep is a 2000. TJ Sahara with 163k miles. Jeep was stock.

We finished installing the lift yesterday, it was pretty straight forward, I tightened everything when the Jeep was on the ground, re-centered the steering wheel and lowered the tire pressure to 33psi.

Right now the Jeep has some vibration that feels like it's coming from the driveline. It also has an annoying little squeak that I hear at low speeds and the rhythm is set by the speed. I checked and nothing is rubbing anywhere.

I have researched and found that if I lift 4" or higher I might need a SYE, I don't think the Jeep is lifted that high, I' was expecting 2" maybe 2.5" but I have no frame of reference since i did not take any before measurements. Below are some pictures for reference.

What should I look for trying to diagnose this vibration? The Jeep drove nice and smooth before the lift.

IMG_8074.jpgIMG_8077.JPG


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If you can feel the vibration in the shifter or gas pedal while driving, you need an sye kit. If it's in the steering wheel, it's a suspension issue or wheel/tire problem.


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Sound advice above, I would start by taking the front shaft out. If that eliminates most of the vibes it can be solved by getting a proper alignment done. They need to balance your caster vs. pinion angle. Ideally your front pinion should be directly in-line with the TC output nut. This may be impossible without loosing to much caster, that’s why I say a nice balance between the two may be necessary.

Find out how much lift you have gained. Just google stock belly height for your year and re measure.

It is actually most likely the rear pinion angle that’s your issue. Just this one costs money. Although it can be alleviated same as the front only with less Ujoint tolerance as it’s not a Double Cardin DS like the front. Therefore the pinion ideally should have the exact angle as the rear TC output nut which is almost impossible after a lift.

Few solutions for the rear. You can drop the transfer case. (Cheap kits available and not ideal) Hack and tap the rear TC output shaft and buy a double cardin DS. Or full SYE and driveshaft.

Sorry for the rant..

Out of curiosity what rear axle is in it? (2avail from the factory)




Cheers.
 
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