Synergy Manufacturing source wording says: Fitment: Part # Description 4127 2007 - 2017 Jeep JK / JKU 4127KN 2007 - 2017 Jeep JK / JKU Benefits: Fully adjustable and rebuildable lowers are designed to last the life of the vehicle, without ever having to press them out of the inner-c On and off road tested for more than 5 years and 500,000 miles providing time tested components you can trust Best in class price to performance ratio Compatible with all aftermarket axle shafts (including RCV's) with no modifications needed Fully greaseable metal on metal ball Joint bearing surface has considerably larger area than stock due to elimination of the inner nylon liner for a longer lasting joint Heavy duty, heat treated stud prevents unwanted movement and premature failure Improves road manners and corrects sloppy steering Features: Patent Pending Lower Ball Joints are adjustable and rebuildable so they always have the correct amount of preload Knurled and non-knurled ball joint housing options to fit any vehicle CNC machined lower ball joint surfaces from 4140 steel, heat treated, induction hardened, and ferritic nitrocarburized for extreme wear resistance Heavy duty, extra large 4140 steel stud for maximum strength and reliability Low profile dust boots are made from thick nitrobutile rubber (NBR) protect the joint from contaminants and eliminate any chance of tearing Limited Lifetime Warranty Zerk fittings included for trouble-free maintenance Includes: 4127 4127KN (2) Upper Ball Joints (2) Lower Adjustable Ball Joints (1) Ball Joint Hardware Kit for all joints (1) Ball Joint Adjuster Wrench to set pre-load (2) Knurled Upper Ball Joints (2) Lower Adjustable Knurled Ball Joints (1) Ball Joint Hardware Kit for all joints (1) Ball Joint Adjuster Wrench to set pre-load Notes: Synergy 4119 High Performance Grease recommended Knurled ball joints required when replacing knurled ball joints that have enlarged the axle end forging bores Non-Knurled ball joints recommended for replacing non-knurled ball joints Due to these ball joints being tight tolerance, metal on metal ball joints, proper fitment is critical.. Verify JK/JL/JT application, axle/trim, tie-rod or drag-link setup, stabilizer/mount path, alignment, and any required brackets before checkout.
Synergy Manufacturing
Synergy Jeep JK / JKU Adjustable Ball Joint Kit
Vendor fitment: 2007-2017 JK Wrangler. Steering fitment from the vendor source. Confirm final options and fitment on the vendor page before purchase.
Our Synergy Jeep JK / JKU Adjustable Ball Joint Kit has endured over 5 years of development and over 500,000 test miles! This is the last set of ball joints you will ever have to buy with a Limited Lifetime Warranty. Tighten up your steering for good with our patent-pending (# 16/020894) design which is fully adjustable, serviceable, and rebuildable without having to press the ball joints back out of the axle end forging yokes (C's). These ball joints never have to come back out. Available in knurled and non-knurled versions to fit all vehicles regardless of what type of ball joints were installed previously. Lower ball joint bearing surfaces are CNC machined from 4140 steel, heat treated...
SKU
JEEP-BALLJOINT
Price
$375
Role
review candidate
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Fact summary
Models: JK Wrangler; Years: 2007-2017; Source: xcart_html; Captured: 2026-05-12