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RockJock Pro Edition Johnny Joint Suspension System for JL Wrangler w/ 392 Hemi, 3.5 in. lift
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4,300.00 4300.0 USD 4,300.00

4,300.00

Not Available For Sale

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Fitment guarantee Ships from Orem, UT 4–8 hr install
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RockJock Pro Edition Johnny Joint Suspension System for JL Wrangler w/ 392 Hemi, 3.5 in. lift

RockJock Pro Edition Johnny Joint Suspension System for JL Wrangler w/ 392 Hemi, 3.5 in. lift
SKU: RJ-JL3921-101
Pick your vehicle to confirm fit

4,300.00 4300.0 USD 4,300.00

4,300.00

Not Available For Sale

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Alignment recommended Lifetime warranty Made in USA

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 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 of Core 4x4

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5.0
132 reviews
5
97%
4
2%
3
0%
2
1%
1
0%
OJ
Oldgreg jr Mar 23, 2025
Google
Good company, they offer well built parts and Great customer service. I had a couple of hang ups with my control arms that I purchased, they were very easy to work with and found the solution to make them work.
EG
Erica Grissom May 27, 2025
Google
First off, I wish I knew about them sooner. The customer service is top tier. The response time is about 30 min no waiting 1-3 days to get a response. The parts are heavy-duty and look amazing. The packaging is perfect, I can't wait to hit some trails. Thanks Core4x4
TW
Travis Walker Sep 24, 2025
Google
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.
Review photo 1 Review photo 2
BW
Brian Wadsworth Jun 26, 2025
Google
Amazing product! Shipping was quick, packaging was great and support was outstanding!!
GK
GLENN KOSZKA Apr 27, 2025
Google
The folks at Core 4X4 are always wonderful to deal with. They explain your options and never pressure or rush things. The quality of the Core Control Arms is top shelf, especially if your goal is to stop wheel hop. I recommend Core 4x4 without reservation ! ! !
MR
Melanee Raynes Mar 25, 2019
Google
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!
MH
Matthew Handy Sep 24, 2025
Google
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.
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.
D
DSI Jul 26, 2025
Google
Great products with excellent customer service after the sale
P
Paul Mar 24, 2023
Google
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.

Specifications

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