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RockJock Pro Edition Johnny Joint Suspension System for JL Wrangler w/ 392 Hemi, 3.5 in. lift

SKU: RJ-JL3921-101
Fits: 2018 - Present Jeep Wrangler JL / JLU Add vehicle

4,080.00 4080.0 USD 4,080.00

4,080.00

Not Available For Sale

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4–8 hr install Moderate Alignment recommended Lifetime warranty Made in USA

RockJock's Pro Edition Johnny Joint Suspension System for JL Wrangler Unlimiteds (4-door) with the 392 Hemi engine provides 3 1/2 inches of lift and allows for efficient clearance of up to 37 in. tall tires (with minor trimming, larger tires will require aftermarket fenders). This kit is comprised of only the highest end components in the areas of strength, fit, finish, function, and the engineering to back them. This kit is designed specifically for the serious off-roader who not only wants to lift their vehicle and install big tires, but also wants to tackle the toughest trails in the country with confidence and ease.Included in this kit is the full set of 8 Johnny Joint adjustable control arms, set of 4 progressively wound coil springs including one front and one rear coil spring shim, front (392 specific) and rear bump stop kits, Johnny Joint adjustable front and rear trac bars, 392 specific rear trac bar geometry relocation bracket, front and rear adjustable extended sway bar links and front brake line relocation brackets. For the ultimate off roading package, you'll want to look at all of the upgrade parts that RockJock has to offer that can be added to this kit to finish this build off! Next level offerings such Antirock Sway Bars and Currectlync Heavy Duty Steering are a must for serious off-roading! Shock options to suite this kit are available from all of the top suppliers.

Make Model Submodel Years
Jeep Wrangler 2018 - Present

Vehicle Jeep Wrangler JL / JLU (18–Present)
Brand RockJock

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Reviews from Google

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5.0
132 reviews
5
97%
4
2%
3
0%
2
1%
1
0%
AP
Ajay Paynter Mar 4, 2026
Google
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.
RC
Ryan Colligan Mar 4, 2026
Google
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.
MT
Marcus Torres Jan 15, 2026
Google
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.
D
David Nov 23, 2025
Google
First of I just want to say Great customer service korby Has helped me from the start and has not let me down! Reached out to him again today and he was able to warranty some parts out for me. As far as the quality of the parts.. excellent! The build quality is great. I can definitely tell a Difference from the cheap oem rear control arms to these and the pan hard bar. Color, From what I can tell it’s super durable been through a few mud holes on top of the daily road grime and after a quick wipe they still pop! Overall I recommend. Customer service is everything for me and it’s definitely there at Core 4x4.
LS
Leonard Smith Jan 22, 2026
Google
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.
PG
Paul Griffin Feb 21, 2026
Google
Great long arm kit with everything else I needed as well! They worked with me to ensure that I was getting an upgraded components kit just like I wanted. Fast shipping with some of the best packaging that I have ever seen. Nothing was scratched or missing and this kit is even more impressive than the videos or website can show. Powder coating looks great with no issues. I would highly recommend CORE 4x4 to anyone looking for a great quality kit.
MM
MIKE (Mike the Mechanic) Jul 26, 2025
Google
Amazing company and customer service!!!! I messed up on my order and the fixed it immediately. Would definitely recommend them. Can't wait to hit the trails with their product.
OK
oleg k Nov 23, 2025
Google
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.
EL
Eric Labrum May 27, 2025
Google
Best customer service I have ever experienced. They are my go to source do to quality and service
SA
Samuel “SamDaman904” Anscher Mar 23, 2024
Google
I meant to put this reviewing about a year ago now, but ever since I’ve had the core 4 x 4, upper and lower control arms on my 2017 ram 1500, they have worked flawlessly leave been on many offering chips, and I’ll definitely be buying new accessories from them in the future and their new upper control arms that they’re offering for all of the ram trucks. Fantastic customer service fantastic health very automotive, off-road, friendly, and any aftermarket thing for your truck or SUV that they currently have!
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