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The Best Upgrades and Mods for Your Jeep YJ

Josh is a Jeep enthusiast with lots of helpful information for readers and Jeep owners.

Do you know the best modifications for your Jeep YJ?

Do you know the best modifications for your Jeep YJ?

Ditch Those Track Bars

Sway bars in red, track bar in blue.

Sway bars in red, track bar in blue.

That's right! Jeep and Chrysler gave you extra parts for a reason.

  • The background: When Jeep altered the beloved CJ to create the love-it-or-hate-it YJ, they added much flatter and softer leaf springs. While this meant that they were a little more agile and with a smoother ride, it also meant that sway bars were necessary if someone wanted even a chance to control this new Jeep on the highway. To be extra safe, they added a track bar on the front and rear as well.
  • The problem: The leaf springs are designed to move up and down, but the track bar moves in an arc. This act of constantly fighting each other puts an extraordinary amount of stress on the frame and axle where it is attached. This force can rip the bars off, or even crack your frame or axle—not worth it.
  • The improvement: Ditch that thing. It's fine. Really. You'll enjoy a better ride and more articulation.
  • For more axle movement: Grab a pair of sway bar disconnects so you can ditch that too when you want to for more off-road capabilities, and then reattach so you can keep it between the lines on the ride home! Just make sure you get the right size for your amount of lift.

Fender Flares

TJ flares on a YJ is a cheap way to gain clearance for bigger tires.

TJ flares on a YJ is a cheap way to gain clearance for bigger tires.

Here is an easy upgrade to fit those larger tires and improve the look of your ride.

  • The problem: The YJ's fenderwells are much smaller than the CJ or TJ's, providing less coverage over those new Super Swampers you just bought.
  • The improvement: By simply replacing your's with the plastic fender flares from your buddy's TJ when he is not looking, you can gain almost 2 inches more up-travel and more tub clearance, without even trimming.
  • A better option if you don't want to lose your wheeling buddy, or if you don't want his old ugly faded grey flares, is to get some shiny new TJ replacements on the cheap. Complete sets can be found online for around $130.
  • Or you can get yourself some big ol' pocket-style flares that provide 6" of coverage and look way better.
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Dana 44

A Dana 44 on the left and a Dana 35 on the right.

A Dana 44 on the left and a Dana 35 on the right.

The legendary Dana 44. It was standard on CJ-7s as a rear axle but became optional for the YJs.

  • The problem: Most YJs ended up with the baby brother—the Dana 35—which was considered junk. The Dana 35 is much weaker than the Dana 44.
  • How to check: To determine which axle you already have, look at the differential on either the front or rear axle: If your differential is shaped like a hexagon, you have a Dana 44. You may now skip this section. But if your axle is round and shaped like an oval, keep reading—you've got yourself a wimpy Dana 35.
  • The improvement: Fear not, D35 owners, D44s are actually pretty easy to come by. How many Jeep Cherokees do you see driving around every day? Chances are, they have a Dana 44 in the rear, and there are just as many at your local junkyard.
  • You can also be on the lookout for a Ford 8.8. This too is an improvement that will fit and is common on Ford products from an '82 F-150 to a current production Mustang.
  • Note that this is a fairly serious mod and is probably unnecessary for someone who only takes their YJ on the highway, with no lift and stock tires. However, if you run your Jeep like it was made to be run—lifted, larger tires, and off-road, sticking a Dana 44 in the rear is a worthy investment to keep you from being stuck out in the woods with a snapped axle. It happens far too often.

Greasable Shackles

A Jeep with boomerang shackles on the front.

A Jeep with boomerang shackles on the front.

This one is easy. Replace those 20+-year-old shackles with some grease-able ones. This will make them last another 20 years. Also, more importantly, you won't sound like a dog's squeaky toy running down the road. This also allows for easier movement and less stress on all parts involved.

  • Feel free to gain an inch of lift, but don't overdo it. Never use shackles that add over 1.5" of lift. It's dangerous, bad for your car, will result in a poor ride and performance, and looks terrible.
  • As a bonus, grab a pair of boomerang shackles for the most improvement in ride and articulation.
  • Replacement shackles will run you anywhere, from $40 for a little improvement to upwards of $120 for a dramatic improvement.
  • They also have some bizarre shackle systems that even flex and twist. They'd better be great for $237 a pair!

4x4 Posi Lock

Make 4WD work every time. Leave the vacuum at home.

Make 4WD work every time. Leave the vacuum at home.

  • The problem: The Achilles heel of Jeeps. I have no idea how this problem has been going on for so long, but did you know that the only thing getting your YJ in and out of 4WD is a small plastic vacuum pump sitting on the underside of your car? Do you know what happens when plastic parts meet rocks on the trail? The rock usually wins.
  • The improvement: Do yourself a favor and spend the $160 (plus shipping) and get the 4x4 Posi Lock, which includes new housing, cable, hardware, and instructions, allowing you to manually engage your front axle from inside the cab.

This is definitely my next investment because as I write this, mine is currently a 2-wheel drive embarrassment with a busted O.E. engagement vacuum. Don't wait to be on the trail to discover you can't engage 4WD. Upgrade to something reliable.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

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