RockJock's custom, small hex 1 1/4 in.-12 left hand thread jam nut that is included in our CE-9114BL threaded bung kit.
| Brand | RockJock |
See It Installed
Install videos and build guides on our YouTube channel.
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132 reviews
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Ajay Paynter
Mar 4, 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 they went above and beyond to make it happen. Quality of the parts is top notch.
RC
Ryan Colligan
Mar 4, 2026
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I have nothing but good things to say about Core 4x4. I have the crawler series on my JKU and we take it all over the place. These parts handle everything we throw at them.
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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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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.
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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.
AH
Abbey Hiett
Mar 25, 2019
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Company finally made things right
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Mike Nielsen
Nov 23, 2025
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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!
JT
jacob trice
Apr 27, 2025
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Core 4x4 has outstanding products at a fair price and unmatched customer service. When you call Korby, it's like talking with a friend. Very cool and helpul!
I ordered some custom control arms, but from the wrong product line and they were super cool about returning them and upgrading to a better "Crawl" series. Only charged the difference between the two products. They paid all the return shipping and sent the uprgaded arms super quick. It was only a couple days. Awesome!!
I couldn't be happier with the transaction👍🏼
Also, these control arms are stout and take a beating. I run heck out my Jeep in the rocks and desert. No problems whatsoever.
Thanks Core 4x4, ya'll are welcome at my campfire anytime!
Jake T.
Pleasant Hill, Or.
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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👌🏽
RP
Robin Poole
Jul 26, 2025
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I had several questions before my purchase and Korby helped me with the correct parts to order and recommendations. Outstanding customer service and product knowledge! Can't wait to install them!