Synergy Jeep TJ/TJL/YJ/XJ/ZJ HD Knurled Front Ball Joint Set Dana 30/44 - 4120-04

The Synergy Jeep TJ / LJ / ZJ / XJ / MJ / YJ Heavy Duty Ball Joint Kit is engineered to withstand the increased loads and abuse that come with lifted Jeeps, oversized tires, and aggressive off-road use. Developed through 5+ years of testing and over 500,000 miles of real-world abuse, these ball joints deliver the strength, durability, and reliability needed to keep your front end performing at its best.

Featuring a fully greaseable metal-on-metal design, Synergy Heavy Duty Ball Joints eliminate the weak factory nylon liner and provide a larger bearing surface for increased strength and longevity. This robust design improves serviceability, extends lifespan, and maintains precise steering and suspension performance even under demanding conditions.

If your Jeep sees bigger tires, harder trails, or increased off-road abuse, upgrade to ball joints built to handle the load.

Fitment:

See our Synergy HD Ball Joints for 1999 - 2004 Jeep Grand Cherokee WJ and 2007 - 2017 Jeep Wrangler JK / JKU models here!

Benefits:

• Compatible with all aftermarket axle shafts (including RCV's) with no modifications needed
• Without the inner nylon liner, the ball joint bearing is significantly larger than stock leading to a longer lasting joint
• Maximum strength and reliability due to the heavy duty steel design on all hard components
• Heavy duty dust boots are made out of industrial grade, wear and tear resistant black nitro-butyl rubber (NBR) to prevent premature rips or tears
• Available in both knurled and non-knurled options
• Fully greaseable, metal on metal design provides smooth operation and 

Features:

• Sintered graphite & oil impregnated bronze ball joint bearing race for a strong, smooth, bearing surface
• 1045 high carbon alloy steel ball joint housing
• Ball joint stud is induction heat treated 4140 chromoly steel for maximum strength and reliability
• Industrial grade, wear and tear resistant black nitro-butyl rubber (NBR) dust boots

Includes:

Notes:

• Synergy High Performance Grease part number 4119 recommended
• Replacement Castle Nut Sizes: 
  • Uppers - 9/16-18"
  • Lowers - 5/8-18"
• Metal on metal ball joints require a small break-in period of typically 100-500 miles to fully "seat" the bearing surfaces. During this time the steering may feel "sticky" or slow to "return to center". Once broken in, the steering will be smooth and tight
• Knurled ball joints are required when replacing ball joints that have enlarged ball joint bores; It is up to the installer to verify proper fitment