Made in USA
Orem, Utah
Lifetime Guarantee
Unconditional
10 Colors
In-house powder coat
Fully Adjustable
0-6" of lift
3 X-Series Options
Only Core 4x4
RockJock's Front Axle Housing Johnny Joint Kit for JK Wrangler and Unlimited vehicles replaces the front differential housing upper control arm bushings Johnny Joint rod ends to get maximum articulation out of your suspension! This kit includes a Johnny Joint insert for gear case ear and installation tool, as well as 1 in. thick flame-cut steel upright for the tube side, with the Johnny Joint already installed. This kit has you cut off the top of the stock bracket that is on the tube and install the new RockJock piece into the existing bracket base. You then weld the RockJock piece to the existing bracket base. This allows for no welding to be done on the tube, resulting in no warpage of the tube. This kit requires cutting and welding equipment for installation! Greasable hardware included. NOTE: this kit is for use on any factory Dana 30 or 44 differential only!
| Make | Model | Submodel | Years |
|---|---|---|---|
| Jeep | Wrangler | 2007 - 2018 |
| Brand | RockJock |
Reviews of Core 4x4
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132 reviews
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Matt
Mar 23, 2024
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The best products on the market. 95% of my xj is core 4x4 products
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luke
Mar 24, 2021
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Excellent quality product and service. My l lower control arms broke and within the same day core 4x4 hooked me up with tier 2 arms and with the color I wanted. My Jeep rides better and has been solid for several months so far. 10/10 would recommend their products to anyone.
JL
John Luna
Nov 23, 2025
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Great team, and help to support my jeep and provide best stuffs
JS
Jeffrey Shafer
Jan 22, 2026
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Exceptional customer service. All my questions were asked in a timely manner and parts were replaced when an error occured. I encourage people to make purchases due to their exceptional quality products, but also because of their customer service. Will make additional purchases in the future.
RM
R2d2 Movi78
Feb 21, 2026
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I’m extremely impressed with Core 4x4. The quality of their parts is outstanding — everything feels solid, well‑built, and engineered with real attention to detail. Shipping was fast and everything arrived perfectly packaged. Their customer service is just as good as their products: responsive, helpful, and genuinely committed to making sure you get exactly what you need.
Overall, a top‑tier experience. I’ll definitely be buying from them again. Specially thank you Mr. Linscomb from Core 4x4. Arturo M.
BA
bryan angell
Jun 26, 2025
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First off amazing products. I got a set of adjustable control arms for my XJ and it is so nice to be able to dial in caster and pinion angles. A quick call and I was able to purchase an adjustable track.
JJ
JT JT
Dec 23, 2025
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We have all shopped places where the person on the phone makes you feel like they don't have the time to talk to you the customer or answer your questions. I can tell you first hand that's not Core 4x4. They have the best customer service I have seen so far. They have taken the time to respond to all of my questions in a very prompt and professional manner, taking the time to answer each and every question I have had. Lets put it this way if Core 4x4 sells a product I am wanting for my truck I will buy it from them, I highly recommend Core 4x4.
JM
Jay Miller
Jul 26, 2025
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I purchased a upper and lower set of control arms from core 4x4 they came early then expected and seem to be very nice quality I ran into a complication installing them and emailed them my question I was expecting to get the response maybe the next day because it was after hours I got a response in about a few minutes which allowed me to finish the project that day I super appreciate that, the products are good strong lifetime warranty and their customer service is top notch
SH
Shawn Hooten
Apr 27, 2025
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Great products, shipped the next day during a big sale event. Core 4x4 gets it right and gets it done! Thank you all.
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Devan Nelson
Mar 25, 2019
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Had a great experience with Core 4x4, I desperately needed a custom track bar and found out just a couple days before Easter Jeep Safari. Spence was a huge help and made it happen with plenty of time to spare. Their parts are top notch!
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Specifications
| Brand | RockJock |
