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Synergy Jeep JL / JLU / JT Heavy Duty Ball Joint Kits

Part #: 4170-XX
Weight: 4 lbs
  • MSRP: $150.00
Purchase through our Dealer Network.
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  • Weight
    3 lbs
  • SKU

Replace your Jeep JL / JLU Wrangler or JT Gladiator's factory ball joints with Synergy MFG's NEW Heavy Duty Ball Joint kit. These ball joints use a metal on metal bearing design, unlike the factory (plastic nylon bearing design), to improve durability and performance. A must for vehicles with lifts and larger tires that see off road use. Get rid of that steering wander and play caused by loose or worn out ball joints. While Jeep may have updated the JL / JLU and JT steering knuckle to use a dual load bearing upper and lower ball joint, they still kept the problematic nylon inner liner which is prone to premature wear. Our Heavy Duty Ball Joints feature the latest design used in our other ball joint applications with our proven design that are sure to stand the test of time.


  • Compatible with all aftermarket axle shafts (including RCV's) with no modifications needed
  • Fully greaseable metal on metal design for prolonged life
  • Ball Joint bearing surface area is considerably larger than stock due to elimination of the inner nylon liner for a longer lasting joint
  • Ball joint bearing race is manufactured from sintered graphite & oil impregnated bronze for a strong, smooth, bearing surface
  • Ball joint housing is manufactured from 1045 high carbon alloy steel for a strong, smooth, bearing surface
  • Ball joint stud is manufactured from induction heat treated 4140 Chromoly steel for maximum strength & reliability
  • Ball joint dust boots are made from an industrial grade, wear/tear resistant black nitro-butyl rubber (NBR)
  • 12 Month Unlimited-Warranty (see warranty information)
  • Synergy High Performance Grease (4119) recommended


  • 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 the axle end forging bores
  • It is up to the installer to verify the proper ball joint style is being used
  • Part Number 4170-60 Includes (2) 4170-01
  • Part Number 4170-12 Includes (2) 4170-04
Part #ApplicationIncludesKnurled
4170-01JL / JLU / JT1 Upper / 1 LowerNo
4170-60JL / JLU / JT2 Upper / 2 LowerNo
4170-04JL / JLU / JT1 Upper / 1 LowerYes
4170-12JL / JLU / JT2 Upper / 2 LowerYes

pdf-icon.gifInstallation Instructions


Synergy HD Ball Joints (above) vs. Mopar Factory Ball Joints (below)
Synergy HD Ball Joints feature a fully greaseable sintered metal on bushing design that has high wear resistance. Outperforms the Mopar factory plastic bushing.


Dana Spicer Uses a Negative coil spring on the wrong side of the load path resulting in Premature wear of the Ball Joints




WARNING: Operating, servicing and maintaining a passenger vehicle or off-road vehicle can expose you to chemicals including engine exhaust, carbon monoxide, phthalates, and lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. To minimize exposure, avoid breathing exhaust, do not idle the engine except as necessary, service your vehicle in a well-ventilated area and wear gloves or wash your hands frequently when servicing your vehicle.
For more information go to www.P65Warnings.ca.gov

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