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 front coil spring shim for JL Wrangler and JT Gladiator is 1/4 in. thick and mounts between the welded on coil spring axle pad and the coil spring isolator. The indexing pin in the coil spring isolator fits thru the hole in this shim to properly clock it. These shims are used to fine tune vehicle height per model, engine combination and added weight load. Shims may be stacked a maximum of 2 high. Semi-gloss black powder coat finish.
| Make | Model | Submodel | Years |
|---|---|---|---|
| Jeep | Gladiator | 2020 - Present | |
| 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
BC
Brad C
Mar 24, 2021
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Outstanding experience! I asked Core to build me a set of custom control arms that were larger/heavier than they normally build. They gladly accepted the challenge and turned out an expertly crafted and super strong product ahead of schedule. Fit and finish are excellent. Spence and Cameron were a pleasure to work with every step of the way. And all of this for a very reasonable price. I highly recommend these guys!
TM
Tony Moller
Aug 25, 2025
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★
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Awesome parts! Support the older Jeeps! Great customer service.
SA
Samuel “SamDaman904” Anscher
Mar 23, 2024
★
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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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niceguyr1
Mar 24, 2023
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I purchased upper and lower adjustable arms for my WJ and lowers were missing the spacers. I didn't know until 3 months later when I was installing them. With absolutely zero hassles they quickly sent me the missing spacers. Fantastic product and service! Huge thank you guys for the awesome service and parts!!! Customer service is quickly becoming a lost commodity and you guys gave me hope that it's still alive and well, you just have to buy from the right people... Thanks again for going above and beyond! 👍👍
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luke
Mar 24, 2021
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★
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Excellent quality product and service. My l lower control arms broke and within the same day core 4x4 hooked me up with tier 2 arms and with the color I wanted. My Jeep rides better and has been solid for several months so far. 10/10 would recommend their products to anyone.
SH
Shawn Hooten
Apr 27, 2025
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Great products, shipped the next day during a big sale event. Core 4x4 gets it right and gets it done! Thank you all.
TG
Travis Grimm
Mar 23, 2024
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To start off if you're looking to upgrade your control arms definitely hit this company up. Great product, easy install of the product, with three different tiers everything is priced pretty good, I'm a sticker guy and they sent a sticker for each arm each track bar and also three extra ones so the extra are on the Jeep the advertise them for sure. If you're reading this review I highly recommend you to check their website out.
AP
Ajay Paynter
Mar 9, 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 of possibly not getting the control arms in time. Quality is amazing on the part, affordable price for what you get, and the powdercoat is top notch, not a single issue with this product, would buy again.
MN
Mike Nielsen
Nov 23, 2025
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★
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The customer service is first class. I had an issue with a track bar I installed on my F350. I don’t have any other Core 4x4 parts yet, but with the way I was treated, I know their parts are well done, because they went above and beyond to make sure I was made whole. They wouldn’t be in business if they had to take care of a lot of people like they took care of me. Will definitely be back when it’s time to build the Jeep!
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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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Specifications
| Vehicle | Jeep Gladiator JT (20–Present), Jeep Wrangler JL / JLU (18–Present) |
| Brand | RockJock |
