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 Uni-Balls for Front Axle Housings are used in 3-link suspension applications, where the passenger’s side upper control arm has been eliminated and all of the suspension load is now being applied to the one axle housing mounting location. Our Uni-Balls press into the stock bushing holes on the casting side, driver’s side ONLY) of the front differential housing and provide a durable solution that incorporates a 5/8 in. thru-bolt hole for heavier hardware. This Uni-Ball will press into a stock JK or a stock TJ/LJ/XJ/MJ/ZJ housing, as well as aftermarket replacement differentials from companies such as Dana, UD-60s), Dynatrac, East Coast Gear, Fusion 4x4 and Currie Enterprises, cast center housings ONLY, does not apply to 9 in. / fabricated style differentials). Additionally, “most in. aftermarket differentials that are intended for installation in a JL/JT vehicle, still retain the bushing specs. of a JK bushing, making this the applicable Uni-Ball to install in an aftermarket differential, again, cast center only, not 9 in. style going into a JL/JT., for STOCK JL/JT housings, see our RJ-301002-101 Uni-Ball. The mounting width of the center pivoting assembly is 2 in., to allow it to fit into the fork on JL/JT/JK/TJ/LJ/XJ/MJ/XJ front upper control arm, however, the 5/8 in. thru-bolt hole will require drilling of the bolt hole in the control arm fork. Uni-Balls feature a sealed bearing assembly, so no greasing is required. Finish is clear zinc plating.
| Make | Model | Submodel | Years |
|---|---|---|---|
| Jeep | Cherokee | 1984 - 2001 | |
| Jeep | Comanche | 1986 - 1992 | |
| Jeep | Gladiator | 2020 - Present | |
| Jeep | Grand Cherokee | 1993 - 1998 | |
| Jeep | Wrangler | 1997 - 2006 | |
| Jeep | Wrangler | 2004 - 2006 | |
| Jeep | Wrangler | 2007 - 2018 | |
| Jeep | Wrangler | 2018 - Present |
| Vehicle | Jeep Gladiator JT (20–Present) or Jeep Wrangler JL / JLU (18–Present) |
| Brand | RockJock |
Reviews of Core 4x4
5.0
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132 reviews
EC
Eric Cox
Jul 26, 2025
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Prompt, professional, and courteous service! Quality parts and broad assortment of products to suite your 4x4 needs:)
ZA
Zen Asher
Mar 23, 2025
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The quality and durability of the arms are the best. They are super heavy duty. And lifetime warranty is crazy
SG
Sal Giordano
Sep 24, 2025
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I want to take the time to share my experience with Core 4x4.
I have a 2004 Jeep Wrangler and was looking to upgrade some suspension parts. I went with Core 4x4 upper & lower adjustable control arms and a front adjustable track bar. Everything arrived quickly, and right out of the box I was impressed with the quality and craftsmanship.
I had a few questions during installation (measurements and torque specs), and I spoke with Korby on a couple of occasions. Not only did he send me detailed instructions, but he also shared an installation video specific to the part and vehicle I was working on, something you don’t get from many companies.
The control arms fit perfectly, look great, and perform exactly as I hoped. I did run into an issue with the front track bar touching the front diff. When I reached out, Korby had me send pictures and then immediately offered two solutions: his bar guy could make a different bend and send it out to me, or I could get a full refund. His response honestly blew me away. As much as I wanted to run the Core 4x4 track bar, I chose the refund. Korby sent me a prepaid shipping label right away, no hassle.
My experience with Core 4x4 has been excellent. Korby was extremely understanding, communicative, and helpful every step of the way. The parts I received were high quality, and the customer service was second to none.
I would absolutely recommend Core 4x4 10 out of 10 times and will be using them again. Just a great American company with awesome people who truly care about their customers.
Thank you Korby, and thank you Core 4x4!
MG
Morgan Griffith
Mar 25, 2018
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I met a couple of the Core 4x4 guys at the Salt Lake Offroad Expo and decided to try them out after noticing one of my control arm bushings was disintegrated. I called to discuss parts on Thursday and I was leaving for a trip on Saturday. These guys built my control arms and had them ready to be picked up Friday, 24 hours later. The parts seem to be great quality and they charged me nothing extra to have them painted. These guys were extremely helpful and without them my trip probably would have been cancelled. looking forward to testing out the arms on my next trip to Moab.
EL
Eric Labrum
May 27, 2025
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Best customer service I have ever experienced. They are my go to source do to quality and service
DW
Darin Wuebbels
May 27, 2025
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Thanks for the fabulous customer service. Your products and customer service are first class. I highly recommend these guys. Excellent experience.
DN
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!
MR
Melanee Raynes
Mar 25, 2019
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Awesome product and service! I even got some of their swag because it looked pretty darn good. I will definitely be going back and would suggest this business to others looking for quality control arms. Buy local!
D
Danny
Oct 24, 2025
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Outstanding customer service to match the high quality parts. This is the go-to company.
MB
Melody Baker
Jan 22, 2026
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I ordered a part for my 03 Jeep TJ and all I can say is wow! Korby at Core 4x4 is a total rockstar!! There was a glitch with my payment and within minutes, Korby reached out to me to get it fixed, then sent my receipt with the tracking number. I lost the number and reached out to him during the Holidays and got a rapid response with the number again. I can’t say enough about the customer service and the quality of parts. Thank you!!
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Specifications
| Vehicle | Jeep Gladiator JT (20–Present), Jeep Wrangler JL / JLU (18–Present) |
| Brand | RockJock |
