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
RC
Ryan Colligan
Mar 4, 2026
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I have nothing but good things to say about Core 4x4. I have the crawler series on my JKU and we take it all over the place. These parts handle everything we throw at them.
OK
oleg k
Nov 23, 2025
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I recently ordered a set of control arms from Core 4x4, and the entire experience was absolutely top-notch from start to finish. The ordering process was smooth, the parts arrived quickly, and the control arms themselves are extremely high quality—solid construction, great finish, and clearly built to last.
I also want to give a special shout-out to Korby, the guy I spoke with during the process. His customer service was amazing. He went above and beyond to make sure I got exactly what I needed, answered all my questions, and made the whole experience stress-free. You don’t see service like that very often these days.
If you’re looking for high-quality suspension components backed by truly exceptional customer service, I highly recommend Core 4x4. I’ll definitely be buying from them again.
RP
Robin Poole
Jul 26, 2025
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I had several questions before my purchase and Korby helped me with the correct parts to order and recommendations. Outstanding customer service and product knowledge! Can't wait to install them!
E(
Eric Hernandez (savagefit)
May 27, 2025
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The whole process was quick and painless. The products are top tier and when I reached out them for package update info, Korby Linscomb was very responsive, and got me the answers I needed the same day. Even when I emailed back to some additional info, he sent what I was looking for that same day. I love core 4x4 and will be giving them my business from now on.
P
Paul
Mar 24, 2023
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I've been having trouble with the track bar (on my 2nd gen Dodge) since I installed the 3rd gen Synergy adapter bracket and a 3rd gen stock bar.. oddly, they call it a '3rd gen bracket' and the stock 3rd gen bar doesn't quite fit, making contact with the bracket. I had attempted to clearance the bracket but it was still making contact and I could feel it over large bumps.
I reached out to a lot of companies, but Core 4x4 offered to make a custom bar for the application with adjustability and dual Johnny joints. The first pass on it didn't work but they sent me out another passenger side end that made it fit incredibly well.
This was all done solely over email/descriptions/pictures/measurements.
Bar is super high quality and heavy duty, made in the US by a family owned company and carries a lifetime warranty. The customer service was responsive and superb, and the price was a lot less than I expected.
AM
Adam M
Sep 24, 2025
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First time buying from Korby @ Core 4x4 and it’s being nothing short of a great experience. I bought the non adjustable Trail kit for my 5th Gen Ram 1500 with a 2” lift. The welds look great, nice powder coat finish and quality bushing. Had some trouble fitting the grease nipples due to the powder coating but a thread tap would fix that. They fit easily and perform great. I felt the improvement straight away. No more wheel hop on hard acceleration which was my main reason for the purchase.
I was missing some smaller bushings needed for the 5th Gen and Korby’s custom service was on point, with responsive emails and mailing out the missing parts straight away. Very happy with their products and customer service. Highly recommended company👌🏽
CL
Colten Lockwood
Mar 25, 2019
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Recieved warrenty exchanges for my control arms last night couldnt be happier!!! Lets talk about the arms tho! Great quality arms in multiple styles and colors!!! I purchased the teir 3 short arns for my 98 xj. I can say that they setoff nicely so my 35 inch tires do not rub! As long as you can get a photo or video of broken hardware core will take care of you. The body of the arm is bulletproof. However make sure to maintain and grease the joints regularly as with any greaseable joint and they shouldkast forever. I had a few problems arise a year after purchase and after some troubleshooting spence was able to help get me the correct parts to get back on the road. I recommend this setup to any and all jeepers looking to get away from the stock arm setup. Alltogether i am Very happy with the performace of my control arms!!!! Mechanic and bodyman of 12 years and my first choice for quality control arms!!
MH
Matthew Handy
Sep 24, 2025
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Ran into an issue with a part that I ordered. Got ahold of them explained to them the issue I was having and they jumped in and got the issue fixed. Hands down the best customer service I have ever dealt with. The parts are hands down amazing. Highly recommend.
BB
Brayden Brockey
Mar 23, 2024
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Got a set of upper control arms for my xj, really impressed with the quality
TW
Travis Walker
Sep 24, 2025
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I have nothing but great things to say about this company and their customer service. If you like American made products backed by warranty and amazing customer support, this is the company for you. I have a Lexus GX470 and love their rear control arms.
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Specifications
| Vehicle | Jeep Gladiator JT (20–Present), Jeep Wrangler JL / JLU (18–Present) |
| Brand | RockJock |
