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 bump stop kit for Jeep TJ Wrangler and LJ Unlimited vehicles, as well as all XJ, MJ and ZJ, extends the top and bottom bump stop impact points the necessary amount for a 4 in. lift. These quality polyurethane bump stops and aluminum spacers fit inside the coil spring top and bottom. Additionally, this kit positively retains the coil spring to the differential housing. This is a set for the front end only.
| Make | Model | Submodel | Years |
|---|---|---|---|
| Jeep | Cherokee | 1984 - 2001 | |
| Jeep | Comanche | 1986 - 1992 | |
| Jeep | Wrangler | 1997 - 2006 | |
| Jeep | Wrangler | 2004 - 2006 |
| Brand | RockJock |
Reviews of Core 4x4
5.0
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132 reviews
GC
Grant Chaisson
Jun 26, 2025
★
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These guys are awesome!! They have helped me build multiple jeeps from zjs to mjs and now with my lj build they all ways impress.
There products are the best on the market in my eyes. The best part about it all is it's all made right here in american and shipped anywhere in the world 🌎 .
Don't think twice when your looking for control arm or lift kits for your vehicle if these guys sell it BUY IT!!!
LS
Leonard Smith
Jan 22, 2026
★
★
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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.
DD
DANIEL DUSSAULT
Nov 23, 2025
★
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Very beefy items for a very reasonable price. Personally have CORE rear track bar and all upper control arms for my 04 Jeep TJ. Had a slight issue with control arm length and they went above and beyond to swap jam nuts to get me where I needed to be. Really have to appreciate a company like this.
SC
Singer Heating and Cooling
Mar 25, 2018
★
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These guys are great. You can get them on the phone for support. This important and is not always the case with other custom parts builders. Their control arms are bomb proof and offer plenty of options. You can get real genuine Currie Johnny joints without paying the price for Currie arms.
GN
Glenn Nowosad
Jan 22, 2026
★
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I just finished installing the Peak 2.0 Front Suspension system with the Core 4x4 Blue Tacoma Rear Suspension system on my 2024 TRD Offroad Premium Tacoma. The two upgraded suspension systems really made a difference in how the ride feels, whether we’re off-road or on the road. A big thank you to Korby and the team at Core 4x4 for their support and for getting the shipping sorted out so quickly!
JH
Joe Hu
Sep 24, 2025
★
★
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Amazing! I put all my new control arms and it drives a lot smoother and looks great!!!
RH
Rex Hodges
Jun 26, 2025
★
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After ordering an upper and lower adjustable control arm kit manufactured by CORE 4X4 from a jeep parts distributor who's intials are E.T., they came with 3 of the threaded ends missing. After over 2 months of phone calls and emails to this E.T. company nothing was resolved. I finally decided to call CORE 4X4 myself and tell them my dilemma. I spoke with a very personable and professional gentleman named Korby, who is one of CORE 4X4's representatives, after a brief discussion of what I went thru he simply asked me for a picture and some measurements and the items I was missing and asked if I could cover ONLY the cost of shipping and I had my missing parts in exactly 1 weeks time. This company not only builds all it's parts in the U.S.A., they stand behind their products with great customer service and life time warranty. My experience with this company and their Rep Korby was fantastic. I would definitely recommend CORE 4X4 to anyone who needs parts for any 4x4 projects. You just can't beat their quality and service.
Rex Hodges
Valparaiso, Indiana
TH
Todd Hume
Jan 22, 2026
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Their products are great but the service is even better!! Thanks Korby.
DW
Derek Whitfield
Nov 20, 2025
★
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Solid product, the lifetime warranty sealed the deal for me. Installed on my TJ and the ride quality improved noticeably. Shipping took a bit longer than expected but the parts were worth the wait.
MT
Marcus Torres
Jan 15, 2026
★
★
★
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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.
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Specifications
| Brand | RockJock |