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 JL and JT Frame Rail Plugs are a simple, easy to install detail part that help to cleanly finish off a nice build. As axles get wider and aftermarket fenders get installed, these areas of your vehicle become more visible. Plugs are CNC machined black Delrin, providing a semi-gloss black finish. These plugs fit in the large, oval shaped hole in the side of the frame rail, behind front axle center line.
| 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
JM
Jay Miller
Jul 26, 2025
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I purchased a upper and lower set of control arms from core 4x4 they came early then expected and seem to be very nice quality I ran into a complication installing them and emailed them my question I was expecting to get the response maybe the next day because it was after hours I got a response in about a few minutes which allowed me to finish the project that day I super appreciate that, the products are good strong lifetime warranty and their customer service is top notch
CL
Cade Leith
Mar 23, 2024
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Have full upper/lower CA set on both front and rear axles on a 96 ZJ. These are the rubber bushing sets not joint sets. I have beat the hell out it in the Nevada desert for 2 years and has been great. I don’t go fast but I do articulate suspension a lot. Super solid and haven’t any issues. Just inspected the entire set recently due to some banging under it. Turns out the banging is lower rear shock bushings. Inspected each CA along the way nothing. Aside from dirt and obviously winter roads and what not still in excellent condition, bushings are solid like the day they were installed. I’ll add that I’m about tapped on a short arm at 4.25(less with settle) so the front CA’s get beat on just from that, still they’re like new. Paint is great condition, this set is red. I would definitely buy again. Another plus for me, Utah isn’t local necessarily, but it’s nice to support businesses closer to me.
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👌🏽
RT
Ruby Timm
Apr 27, 2025
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Bought a new 2019 Ram 1500. Had bad rear wheel hop since new, got all four core 4x4 control arms and it fixed the issue. Thanks
VK
Victor Keele
Sep 24, 2025
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Great customer service. I got my front upper and lower control arms and hardware on Friday afternoon. It didn’t come with instructions so I called Core 4X4 and they immediately e mailed me the instructions. Also, the kit I got had the spacers missing so I called. It was late Friday by thus time but they took care of the issue first thing Monday morning and I got the spacers on Tuesday. Great company.
L
luke
Mar 24, 2021
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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.
RG
Robert Van Gorder
Apr 27, 2025
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Amazing service. Bought a track bar through Americantrucks.com and they sent it with the wrong size bushing sleeve. Korby at Core 4x4 was quick to get me the correct size and very responsive. Will definitely be using more of their stuff.
PG
Paul Griffin
Feb 21, 2026
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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.
MG
Morgan Griffith
Mar 25, 2018
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I met a couple of the Core 4x4 guys at the Salt Lake Offroad Expo and decided to try them out after noticing one of my control arm bushings was disintegrated. I called to discuss parts on Thursday and I was leaving for a trip on Saturday. These guys built my control arms and had them ready to be picked up Friday, 24 hours later. The parts seem to be great quality and they charged me nothing extra to have them painted. These guys were extremely helpful and without them my trip probably would have been cancelled. looking forward to testing out the arms on my next trip to Moab.
DR
David Rogers
Aug 25, 2025
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Ive had the front adjustable control arm kit in bright green for my 1996 ZJ.
Ive had the kit for about a year now and i have to say, im extremely impressed, over 1000 miles off-road and roughly 20,000 miles on the highway. These control arm kits for any vehicle built by core 4x4 are well worth the money, just be aware thereight be some minor scatches or chips from shipping ( but who should care about that if you're beating the crap out of em' they way they were built and designed for)
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Specifications
| Vehicle | Jeep Gladiator JT (20–Present), Jeep Wrangler JL / JLU (18–Present) |
| Brand | RockJock |