RockJock's narrow forged Johnny Joints for fabricators and suspension system builders offer 40 degrees of unrestricted movement in any direction as compared to 22 degrees on a common heim joint! Johnny Joint rod ends offer cushioning that a heim joint cannot provide via high-density urethane bushing that encases the inner ball. The heat treated center balls are cross-drilled for thru-bolt lubrication and the joint internals are retained with 2 heavy duty, heat treated side washers and a snap ring. This specific joint is a 2 in. diameter, fitted with a zerk fitting for greasing, 2 1/4 in. of 3/4 in.-16 right hand threads on the shank, and a 2 in. mounting width ball with a .4375 in. thru bolt hole. Finished in gold zinc plating.
| Brand | RockJock |
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Ajay Paynter
Mar 4, 2026
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Great company, who worked with me on shipping parts to arrive in time for a show. When I explained my concern they went above and beyond to make it happen. Quality of the parts is top notch.
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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.
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Marcus Torres
Jan 15, 2026
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Best control arms I have installed on any of my builds. After running every major manufacturer, Core 4x4 is on par or better than all the high-end companies at a fraction of the cost. Lifetime warranty is the cherry on top.
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Leonard Smith
Jan 22, 2026
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I don’t write reviews often, but Core 4x4 absolutely earned this one.
I recently ordered leaf spring mounts and realized after the fact that I messed up my order. Totally my mistake. Instead of giving me the runaround or pointing at a return policy, Core 4x4 emailed me back and forth, worked through exactly what I was doing with my build, and made sure I ended up with the correct parts.
That kind of customer service is rare these days — especially in the off-road world where a lot of companies stop caring once the order is placed.
The parts themselves are exactly what you hope for: solid, well-made, confidence-inspiring hardware that looks like it belongs under a vehicle that actually gets used. You can tell these are designed by people who understand suspension geometry and real-world abuse, not just CAD screenshots.
Mistakes happen — especially on custom or modified builds — and Core 4x4 handled mine like pros. Fast responses, clear communication, and a genuine effort to help me get it right.
If you’re on the fence: don’t be. Core 4x4 is the kind of company you want backing your build — the kind that treats customers like fellow enthusiasts, not order numbers.
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Adam
Oct 24, 2025
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I couldn't have been more excited for the initial unboxing of these new Core 4x4 UCA's!
They appear to be so well built and just a true quality product.
Installation was a breeze and the initial testing with the forklift appears to have given me some additional flex with less binding on the rest of the components now that the geometry is back properly aligned.
Time will tell how they hold up on my near future off-road adventures but I don't have any doubt that they are up to the task!
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Reagan D'mello
Dec 23, 2025
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Love the product. Excellent customer support 👍🏽 …
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Chris
Oct 24, 2025
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Great product for a good price. Customer service is top notch, I had an issue which was self cause and Core 4x4 helped me out even though it was my own fault. Would definitely recommend and use them again.
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Grant Chaisson
Jun 26, 2025
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These guys are awesome!! They have helped me build multiple jeeps from zjs to mjs and now with my lj build they all ways impress.
There products are the best on the market in my eyes. The best part about it all is it's all made right here in american and shipped anywhere in the world 🌎 .
Don't think twice when your looking for control arm or lift kits for your vehicle if these guys sell it BUY IT!!!
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Dastrup Auto
Mar 25, 2019
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I have bought a bunch of sets of arms, track bars and even had custom work done by Core 4x4. Just yesterday, Spence and Cam delivered an awesome cross member they designed and built for me! All of their products have been exceptional! I have personally seen their progression with design changes/updates. They truly take pride in their work and products. Quality control is second to none! They’ve also helped me diagnose issues with different jeeps I’ve had, as well as Dodge/Rams. These guys know their stuff! Really! I trust them whole heartedly and absolutely love their products/quality of work! I’ve referred many people, and will always continue to do so. Keep up the good work Core4x4!
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Owen Adams
Sep 24, 2025
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These guys are awesome I messed up my address on my order somehow and they were so so helpful Korby was right there every step to a solution very communicative and respectful I will definitely be ordering parts with them in the future!