Synergy Jeep JL/JT Heavy Duty Ball Joints Knurled (1 Upper/1 Lower)

SKU: 4170-04

Heavy Duty Ball Joint Kit for Jeep Wrangler JL, JLU, and Gladiator JT

Synergy Manufacturing Heavy Duty Ball Joint Kit, the ultimate upgrade for off-road enthusiasts and daily drivers alike. Engineered to replace the factory’s inferior plastic nylon bearing design, these fully greaseable, metal-on-metal ball joints deliver unmatched durability, longevity, and precision steering. Say goodbye to steering wander, play, and premature wear caused by stock ball joints, especially on lifted Jeeps with larger tires. Designed specifically for 2018+ Jeep Wrangler JL, JLU, and 2020+ Gladiator JT, this kit is a must-have for tackling rugged trails or enhancing on-road stability.

Synergy’s Heavy Duty Ball Joints feature a proven metal-on-metal bearing design that eliminates the problematic nylon inner liner found in OEM ball joints, offering a significantly larger bearing surface for extended lifespan. Crafted from heat-treated 4140 Chromoly steel for the stud and 1045 high-carbon alloy steel for the housing, these ball joints provide maximum strength and reliability. The sintered graphite and oil-impregnated bronze race ensures a smooth, durable bearing surface, while industrial-grade nitro-butyl rubber (NBR) dust boots protect against trail debris and resist tearing during maintenance. Compatible with all aftermarket axle shafts, including RCVs, this kit requires no modifications for a seamless bolt-on installation.

Whether you’re conquering rocky terrains or cruising highways, the Synergy Heavy Duty Ball Joint Kit corrects sloppy steering, reduces wear, and enhances road manners. Backed by over 5 years of development and 500,000+ test miles, these ball joints are built to withstand the toughest conditions. Pair them with Synergy’s High-Performance Grease (4119) and Heavy Duty Steering Kit for a bulletproof front-end setup. Upgrade today and experience the Synergy difference—your Jeep deserves the best!

Part Numbers:

• 4170-01 (Non-Knurled, Single Side, 1 Upper/1 Lower)
• 4170-04 (Knurled, Single Side, 1 Upper/1 Lower)
• 4170-60 (Non-Knurled, Pair, 2 Upper/2 Lower)
• 4170-12 (Knurled, Pair, 2 Upper/2 Lower)

Material:

Housing: 1045 High-Carbon Alloy Steel

Stud: Heat-Treated 4140 Chromoly Steel

Bearing Race: Sintered Graphite and Oil-Impregnated Bronze

Dust Boots: Wear-Resistant Nitro-Butyl Rubber (NBR)

Features:

Metal-on-metal bearing design for superior durability

Fully greaseable for easy maintenance

Eliminates factory nylon liner for larger bearing surface

Compatible with aftermarket axle shafts (e.g., RCV)

Knurled and non-knurled options to fit any vehicle

Reduces steering wander and play

Ideal for lifted Jeeps with oversized tires

Installation: 100% bolt-on, no modifications required

Recommended Accessories:

• Synergy High-Performance Grease (Part #4119)
• Synergy JL/JLU/JT Heavy Duty Steering Kit (Part #8825-10)
• Synergy JL/JLU/JT HD Steering Knuckles

Fitment:

• 2018+ Jeep Wrangler JL / JLU (All Models)
• 2020+ Jeep Gladiator JT (All Models)

Warranty: Limited Lifetime Warranty

Country of Origin: Made in the USA

Package Includes:

• Choice of single-side (1 upper, 1 lower) or full kit (2 upper, 2 lower)
• Installation hardware

Why Choose Synergy?

Unrivaled Durability: Outperforms factory plastic bushings and Dana Spicer designs with a robust metal-on-metal construction.

Enhanced Steering Precision: Corrects sloppy steering and eliminates death wobble risks, as outlined in Synergy’s JL/JLU/JT Death Wobble Checklist.

Off-Road Ready: Built for aggressive off-road use, perfect for rock crawling, mudding, or desert running.

Trusted Brand: Synergy Manufacturing is a leader in Jeep aftermarket parts, with a reputation for quality and innovation.