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 3/16 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
GK
GLENN KOSZKA
Apr 27, 2025
★
★
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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 ! ! !
CT
Canon TeSelle
Jun 26, 2025
★
★
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Great Experience. I wanted to make changes to my order and Korby was more than willing to work with me to get everything corrected. Hope to deal with these guys again in the future.
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
RD
Reagan D'mello
Dec 23, 2025
★
★
★
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★
Love the product. Excellent customer support 👍🏽 …
LM
Logan Matejek
May 27, 2025
★
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The parts are a massive improvement over factory. I accidentally ordered the wrong endlinks and they helped me figure out the correct size and sent me new ones.
Definitely an awesome store
MM
Mike Martinez
Aug 25, 2025
★
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★
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★
Phenomenal company - very rare to come by in the automotive industry. Also very impressing. Let me start here. I got a set of yellow sway bar end links for my 19 ram DT (new body style) and let me tell you, I’m hooked. For numerous reasons. One the craftsmanship behind the product is unmatched for sure for without breaking the bank. 2ndly, they stand behind their product. Had a very minor issue and it was resolved in a blink of an eye!!! Insane. Just because of what i listed above i will forever spend my money with core 4x4! And i think you should too! I have no affiliation at all with this company besides being a consumer. I will be ordering my yellow UCAs and the rest of my rear suspension from them here shortly!
Korby on the other hand. The representative that helped me went above and beyond FAST. I hung up the phone with him, and with in no lie 3 minutes he was calling back with an answer. GREAT GREAT GREAT customer service, Korby you and core 4x4 are what give us hope in the car community! With much love and great health to you all!!
A
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!
JT
Jay Taylor
May 27, 2025
★
★
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Had a worn out set of rear upper control arms on my TJ. These were old rubicon express long arms. can’t buy replacements and no one makes a direct fit replacement.
Talked with Korby at core off road sent some measurements and photos and a week later new arms showed up. Packaging was perfect fit was perfect.
Would highly recommend giving these guys a call.
MH
Matthew Handy
Sep 24, 2025
★
★
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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.
MD
Mark DiGrappa
Apr 27, 2025
★
★
★
★
★
First off: Korby, the gentleman that helped me decide on which kit to go with is EASILY the nicest, and most patient person I’ve dealt with, when ordering parts for this build. Second: the quality of the product is INSANE! These parts are so nicely fabricated, then powder coated for extra longevity, and they even offer an aluminum upgrade in some cases (which I went with, to save weight). Having said all of this, the most impressive thing was the lead time. These parts are build to order, and I literally ordered my suspension one week ago, today! Yes, they built, powder coated, packaged, shipped my suspension components (RAM 1500 Track rear trailing arm full set in 7075 aluminum, and front upper control arms), AND they arrived, all within a week! Granted, that I’m only one state away, but WOW!!! One week?! Amazing! So, in sort: excellent products, which arrived excellently packaged (no damage, an boxes not over-stuffed with heavy suspension parts; three boxes total, as opposed to one super heavy one…my back thanks you), super quickly, and customer service that ANY business would be envious of….so, if you’re in the market, absolutely go with Core 4X4!
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Specifications
| Vehicle | Jeep Gladiator JT (20–Present), Jeep Wrangler JL / JLU (18–Present) |
| Brand | RockJock |