Synergy Mfg SYN4127KN Knurled Adjustable Ball Joint Kit for 2007-2018 Jeep JK/WJ For Sale

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- AUTHENTIC PART

Part Brand: Synergy Mfg

Part Number: 4127KN

• 2007-2018 Jeep Wrangler JK/JKU (All trims — Adjustable Ball Joint Kit)
• 1999-2004 Jeep Grand Cherokee WJ (All trims — Adjustable Ball Joint Kit)*

• Heavy‑duty knurled adjustable ball joints designed for improved steering precision
• Patent‑pending fully adjustable and rebuildable lower ball joints
• Includes both upper and lower ball joints with hardware and adjuster tool
• CNC machined 4140 steel construction for superior strength and wear resistance
• Heat‑treated and induction hardened components for long‑lasting durability
• Ferritic nitrocarburized lower ball joint surfaces resist abrasion and wear
• Low‑profile nitrile rubber dust boots protect joints from contaminants
• Zerk grease fittings for easy routine maintenance

• Brand: Synergy Mfg
• Part Number: SYN4127KN
• Application: Knurled adjustable front ball joint kit
• Fitment Years: 2007-2018 (Wrangler JK/JKU); 1999-2004 (Grand Cherokee WJ)*
• Compatible Vehicles: Jeep Wrangler JK/JKU, Jeep Grand Cherokee WJ
• Features: Adjustable and rebuildable metal‑on‑metal ball joints
• Material: High‑strength 4140 steel with heat treatment

• 2x Upper knurled ball joints
• 2x Lower adjustable knurled ball joints
• 1x Ball joint hardware kit (nuts, bolts, grease fittings)
• 1x Ball joint adjuster wrench/tool to set preload

The Synergy Mfg SYN4127KN Knurled Adjustable Ball Joint Kit is a heavy‑duty steering and suspension upgrade engineered for *2007-2018 Jeep Wrangler JK/JKU* and also compatible with *1999-2004 Jeep Grand Cherokee WJ* applications*. Designed as a direct‑replacement performance ball joint set, this kit includes fully adjustable and rebuildable lower joints that let you dial in preload without pressing joints out of the axle forging — a unique feature that enhances steering precision and extends service life. CNC‑machined 4140 steel construction, heat treatment, and nitrocarburized bearing surfaces deliver outstanding durability and resistance to wear from off‑road or daily driving conditions.

This knurled version is intended for use where factory or aftermarket joints have enlarged axle bores; the knurled housings help ensure a secure press fit. Each kit includes all necessary ball joints — upper and lower — plus hardware and an adjuster tool to set pre‑load correctly. The result is tighter, more responsive steering with improved road manners and reduced slop compared with worn or stock joints. With zerk grease fittings and serviceable design, these ball joints can be periodically maintained for long‑term performance.