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Synergy Heavy Duty Front Ball Joint Set 4pc (90-06 Jeep Wrangler YJ & TJ)

ExtremeTerrain no longer carries the Synergy Heavy Duty Front Ball Joint Set 4pc (90-06 Jeep Wrangler YJ & TJ). Please check out Jeep Tie Rods, Ends, & Ball Joints for an updated selection.
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Features, Video & Details

  • Set Includes an Upper and Lower Ball Joints
  • Fully Greasable Metal-On-Metal Bushing Design
  • Replaces Factory-Made Ball Joints
  • Made from Wear-Resistant Silicone Polyurethane
  • 12 Month Unlimited Warranty
  • For Use with Dana 30 and Dana 44
  • Suitable for 1990-2006 Jeep Wrangler YJ & TJ Models

Review & Installation Video

Review & Install Video

Today, we're going to talk through the installation of this kit, which I am going to give a two out of three wrenches. There's no major cutting or drilling necessary to get these installed. However, there is going to be a good bit of disassembly of your front axle to do in order to get these installed. So again, a two out of three wrenches, probably around three hours to get these installed. But we'll talk more about that install in a second. We're also going to talk through the construction and a few of the features of these ball joints. Ball joints are a wear item on any Jeep, and especially if you have big tires on your Jeep and/or you wheel it hard, you are going to wear out your factory ball joints quicker. So when you change them out, going to an upgraded, much stronger, heavier-duty set is definitely a good idea. These ones from Synergy are going to be the same metal-on-metal-style ball joint that you can get from some of the other manufacturers, and they're going to be right around the same price. Synergy has a good name. They make a high-quality part. I would definitely trust installing these in my Jeep, and I think they're a pretty good deal. These are designed to fit in either your Dana 30 or Dana 44 front end in your 1990 to 2006 Wrangler. They are going to come in a kit of four. So you'll have two upper and two lower ball joints to do your entire front axle. As I said before, these are a metal-on-metal ball joint, which is a little bit different from your factory ball joint that actually has a silicone piece on the inside of it. These ball joints are going to be greaseable. They come with all the Zerk fittings that you'll need to get them installed. One thing to point out is that these are a knurled ball joint. So if you don't currently have a knurled ball joint installed in your Jeep, you can go ahead and install a smooth ball joint, or you can go with knurled. But once you've installed a set of knurled ball joints like this one, you're going to have to stick with those. So that is one decision that you'll have to make. So like I said, I am going to give this a two out of three wrenches for installation. There's a good bit of disassembly of that front axle assembly to do in order to get these installed, and you're probably going to need to give yourself around three hours. In order to get a set of ball joints out, the best way to do that is by using a ball joint press. Of course, to get your new ball joints in again, a ball joint press is the best way. You can probably get a ball joint out by hitting it with a big enough hammer. But you always risk damaging that ball joint so that it won't come out easily, damaging your steering knuckle, and you're going to need that press to get the new ones in anyway. So go ahead and either purchase or rent a ball joint press before doing this job. Now, if all of this disassembly of your front axle isn't something you feel comfortable with, that's okay too. You can always take your vehicle to a shop and have those install these ball joints for you. However, if you do want to do this on your own in your driveway, it's certainly something you can tackle. The first step is going to be removing the tire. Then, you're going to have to remove the brake assembly, and in some cases also remove your axle from the axle assembly. Then, you can go ahead and unbolt the steering knuckle and remove it, finally removing the ball joints. The install process is going to be the same in reverse, pressing your new ball joints into place, putting your steering knuckle back together, reinserting your axle shaft, putting the brakes and, finally, the tire back on the Jeep. Again, about three hours, and you will need that ball joint press. This set of ball joints comes in at right around the same price as some of the other heavy-duty ball joints on the market that are going to be designed similarly. So as I said before, I think Synergy has a good name. They make a high-quality product. This does come with a 12-month warranty. So I would trust installing these on my Jeep. However, if you do have some brand loyalty to one of the other brands that makes a heavy-duty ball joint, like I said, they are going to be similar in price. So you can go with one of many options. So if your factory ball joints are worn out, either due to a large tire and/or wheeling your Jeep really hard, going with an upgraded set of aftermarket heavy-duty ball joints is a great idea. Going through this install will take a little bit of time. So if you can do it less frequently by installing a stronger part, I think that that is a really smart idea. So that's my review of the Synergy four-piece heavy-duty front ball joint set, fitting all 1990 to 2006 Wranglers, that you can find right here at

Design and Construction. The Synergy Heavy-duty Front Ball Joint Set is an upgrade from stock which completely eliminates the old nylon liner style for extended durability and performance. The ball joint boots are made from durable wear and tear resisting silicone polyurethane.  Featuring a stud made from 4140 steel and induction heat treated bearing surfaces for the smoothest operation while maintaining the life of the ball joint.

Advantage. The Synergy heavy-duty ball joint set is ideal for replacing your existing factory-made ball joint sets especially if you're lifting your rig. Both the lower and upper ball joint pieces feature fully greasable metal-on-metal bushing design that offers high wear resistance, giving you more security than stock ball joints which are prone to premature wear on lifted Jeeps.

Warranty.  Synergy backs this heavy duty ball joint kit with a 12 month unlimited warranty, giving you full security and value for a solid year. Please see manufacture's warranty for full details.

Application. The Synergy heavy-duty front ball joint set is designed for use with Dana 30 and Dana 44 applications on 1990-2006 Jeep Wrangler YJ & TJ models.

Fitment: 1990 1991 1992 1993 1994 1995 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Details

MPN# 4120

CA Residents: WARNING: Cancer and Reproductive Harm -

What's in the Box
  • (2) Upper ball joints
  • (2) Lower ball joints
Installation Info
Tech Specs
Will it fit my Wrangler?
  • TJ Rubicon 2 Door - 03, 04, 05, 06
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  • TJ Wrangler Unlimited 2 Door - 04, 05, 06
  • YJ Wrangler 2 Door - 90, 91, 92, 93, 94, 95

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Customer Reviews (14) Write a Review

Overall Rating 4.1

out of 5 stars

  • Fit 4.642857 4.6
  • Bang For Your Buck 4.071429 4.1

  • 1/5

    November 03, 2018

    Not happy

    Returned them other parts I got from them r failing I don't feel like paying the labber 2 times.


    Year: 2000Submodel: Wrangler

    Helpful (6)

  • 4/5

    October 21, 2018

    ball joint replacement

    good overall product, grease zurc on lower ball joint could have better placement other than that great product


    Year: 2006Submodel: Rubicon

    Helpful (6)

  • 3/5

    September 24, 2018

    Slightly disappointed

    Easy install, everything went smooth, until i loaded with grease. Only to find out one of the upper boots were bad and already has crack in it. Lower joint has no good position to place grease zerk to maintain and get to once everything back together. We shall see how long these hold up. But probably won't use this brand again. Mine also did not come like the ones pictured with clear boots they were black.


    Year: 2004Submodel: Rubicon

    Helpful (6)

  • 5/5

    August 20, 2018

    great joints

    although I had a shop install them they dd go in smoothly and without issue. wheels are tighter now, i'm happy I went with them.


    Year: 2004Submodel: Wrangler

    Helpful (7)

  • 2/5

    July 14, 2018

    Lowers came in loose

    Purchased these less than 6 months ago. The lowers came in looser than expected, but needed the vehicle so had to install. 6 months later back to my same problems, worn ball joints.


    Year: 2005Submodel: Wrangler

    Helpful (7)

  • 5/5

    July 06, 2018

    Only Time

    Well unfortunately I put these on when I Lifted mt TJ, and found more issues with steering components. So went back to Extreme Terrain and ordered more parts to hopefully fix it. But these went in great very simple to install definet upgrade from stock. How long they'll last only time will tell.


    Year: 2001Submodel: Wrangler

    Helpful (7)

  • 4/5

    May 06, 2018

    Great for the money

    Product was easy to install, only issue was one of the uppers was crossthreaded out of the box. Called manufacturer and the new one was on the way the next day.


    Year: 2003Submodel: Wrangler

    Helpful (10)

  • 4/5

    April 24, 2018

    HD Ball Joints

    Well built, fairly easy to install had a slight bump in steering due to a worn ball joint on drivers side. Decided to change them all. These have one minor flaw in that the lower ball joint has a recessed alemite fitting. The problem is there is not enough area around the fitting to get a grease gun on it. Recommend you buy a taller alemite for the lower ball joint. I will probably have to take it apart again to change the alemite out.


    Year: 2006Submodel: Wrangler

    Helpful (8)

  • 5/5

    October 11, 2017

    Better ride

    Just got them on and I've been happy with prior purchases, so hopefully I will be satisfied with them


    Year: 1997Submodel: Wrangler

    Helpful (8)

  • 5/5

    April 26, 2017

    Synergy Ball Joints

    Intalled ball joints on my 04 TJ Rubicon. Installation was easy. Only think is when you position the zert fitting in the position recommended an normal grease gun can't connect on the fitting.


    Year: 2004Submodel: Rubicon

    Helpful (8)

  • 5/5

    March 25, 2017

    Ball joints

    Shipping was fast and the installation was was easy. I've always dredded this job but it was way better than expected. I would buy this product again.


    Year: 2000Submodel: Wrangler

    Helpful (8)

  • 5/5

    November 01, 2016

    Good ball joint set

    The installation was harder to take off the old than it was to put in the new ball joints. Noticeable difference definitely a positive buy.


    Year: 2004Submodel: Wrangler

    Helpful (8)

  • 5/5

    October 16, 2015

    synergy ball joints

    So far so good on these joints. They are better than my old ones that the shafts seperated when i seperated the spindels from the axles.


    Year: 2002canton ohio

    Helpful (10)

  • 5/5

    June 12, 2015

    Best ball joints on the market for TJ Wrangler

    I was having a problem with death wobble on my lifted Wrangler. I have a 3 inch lift with 33x12.50r 15 tires. I decided to rebuild the entire front end and after doing research I decided on buying Synergy ball joints. They are definitely a high quality replacement over my worn out stock ball joints. I even like the fact that the boots are see through so you can see the grease. The ball joints tightened up my front end and made my Jeep front end feel solid again, and better than brand new. I would recommend that if you plan on lifting your Jeep that you use these ball joints. You won't be disappointed.


    Year: 2000Ogden, KS, USA

    Helpful (11)

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