Sure it's Bigger... but is it actually Better? DISSECTING the JL WRANGLER Front Axle

wayoflife

Administrator
Staff member
I have to say, when the Jeep JL Wrangler first came out, I was pretty impressed with the front axle and all the improvements made to it. Clearly, someone was paying attention to the kinds of bends and breaks we were seeing on the JK Wrangler front axle and it was nice to see these new axles came with beefier brackets, significantly bigger end forgings and of course, larger diameter tubes. However, now that a year has gone by, I have to say that I've reeled in my opinion of it a bit and mainly for dumb things like the drain bolt being located directly on the bottom of the differential and of course, the FAD. But, if there is one real concern of mine, it'd be with the axle tubes.

Although rare, I have personally seen several JK Wrangler Rubicon front axle housings break over the last 12 years. This is of course, no real surprise being that the Rubicon 44 front axle was only a 44 in name and mainly because of its differential and axle shafts. The tubes on it were still just 2.50" in diameter with a 0.25" wall, just like a Dana 30 and a true 44 would have 3" diameter tubes. Needless to say, with the JL Wrangler having tubes that are closer to 3" in diameter, 2.75" to be exact, I was hopeful that they would hold up a lot better but then, I started seeing the same kind of breaks that we saw with the JK.

To be fair, the breaks I've seen so far did occur on JL's that were running hard and fast and in one case, the JL in question crashed into a large rock but even at that, I personally don't think the axle housing should have snapped in half the way they did. It should be noted that both breaks did occur on the passenger side and at the location of the FAD and that is something most of us thought could happen. However, it was only after the breaks that we started to learn just how thick, or should I say, just how thin the wall is of the axle tubes.

Thanks to our good friends over at Dynatrac, we got to see first hand what a JL Wrangler front axle tube looks like compared to a JK Wrangler's. As you can see in the photo below, the JL tube has a diameter of 2.75" and that is a bit bigger than the 2.50" that the JK had but it is still shy of the 3" it really should be. Also, the wall thickness of the tube is only 0.282" and that's just slightly thicker than what it was before.

20190217141254-a22af9db.jpg


Now, don't get me wrong, a thicker wall doesn't necessarily make a tube better. A thin wall tube with a large cross section can offer the same amount of strength as a smaller diameter tube that has a thicker wall and without having the same weight penalty. So, if the JL front axle tubes should be plenty strong in spite of the thinner wall, why bring it up, right? Simply put, the JL Wrangler axles are wider!

The JL Wrangler Sport and Sahara have axles that measure 66.50" wide and that makes them 1" wider than what came on a JK Wrangler. Also, a JL Rubicon has axles that measure an impressive 68" wide and that make them 1.50" wider than a Sport or Sahara and a whole 2.50" wider than a JK. I should note, full width axles typically measure 68.50"! What I'm trying to say is that it's more likely than not that Dana increased the tube diameter of the JL front axle to help compensate for the greater loads created by the wider width of the JL and to help reduce weight and not necessarily to help make it stronger than before. If anything, I don't think it would be a stretch to say that a JL Sport or Sahara housing would be a bit stronger than a JL Rubicon's being that they they use the same tubes and are narrower. And so that there's no confusion, I am specifically talking about the "housing" and NOT the axle shafts or gears.

For comparison sake, the photo below is what a JL Wrangler front axle tube looks like next to the standard tube that is used on a Dynatrac ProRock 44JL.
20190217141256-82138ea9.jpg


As you can see, there really is no comparison. The Dynatrac ProRock 44JL tube kills the JL tube with it's MASSIVE 3.125" diameter tubes and with an impressive 0.50" wall. Just to give you some perspective, this is the same tube that Moby's old ProRock 60 has! :shock:

Here's a shot that shows what a Dynatrac ProRock 44JL tube looks like next to a JL tube and a JK tube.
20190217141249-97abbdff.jpg


While I would be the first to say that the factory front axle on our JL Wrangler Rubicon has been holding up, I'd be lying if I said that we've been pushing it as hard as we could or as hard as we'd prefer, especially after seeing the breaks that we have.

Anyway, I thought a few of you might be interested in some of this. :cool:
 

ddays v2

Member
Impressive to say the least. How does Dynatrac deal with the FAD delete? Honestly, while I'm not really a fan of the FAD, I am in agreement with what it does. I wish Dynatrac offered lockout hubs as an option on their PR44.
I'd retrofit that to mine on my JK. I know there are a couple companies that offere these but man, I wish Dynatrac was one that did...
 

JTCO

Meme King
How does Dynatrac deal with the FAD delete? Honestly, while I'm not really a fan of the FAD, I am in agreement with what it does. I wish Dynatrac offered lockout hubs as an option on their PR44.

They eliminated it all together and include shafts with the housing now.

 

wayoflife

Administrator
Staff member
Impressive to say the least. How does Dynatrac deal with the FAD delete? Honestly, while I'm not really a fan of the FAD, I am in agreement with what it does. I wish Dynatrac offered lockout hubs as an option on their PR44.
I'd retrofit that to mine on my JK. I know there are a couple companies that offere these but man, I wish Dynatrac was one that did...

They eliminated it all together and include shafts with the housing now.

This ^^^

The FAD is eliminate and one piece shafts are used. There are no issues not having the FAD in place or at least, that I could tell so far. Shifting into 4WD and back out again works just fine. You will need a Tazer or the like to turn off the FAD on the computer though to get rid of the light.
 

YAHAHA

New member
This is great information. Is there a description of how the FAD works & why it is a weakness in the stock axle?


It's not just a Jeep, it's an amusement park on wheels.
 

wayoflife

Administrator
Staff member
This is great information. Is there a description of how the FAD works & why it is a weakness in the stock axle?

While I did have my reservations about the the FAD, the system itself seems to work well - way better than the old CAD that the YJ's had years ago. So far, I haven't seen any have issues with how it operates. The breaks we've seen have all been with the housing - the tubes to be exact and where they mate with the FAD unit or there about.
 

JIMBOX

New member
:D Great info--with the tube breaks at the FADS housing WELDS----

Sounds like FCA didn't know about the WELD.HEAT/TUBE CONCENTRICITY LOSS/WEAKEN---

And they were doing so well too--

Thanx

:thumb: JIMBO
 

Jeeeep

Member
well that sucks, I was hoping the axle would be one less future replacement item.

Not that I plan to be doing anything to push it hard enough to break it, but I know I've picked wrong lines or slid in the wrong direction and have taken a hit on the PR44 :doh:

Good to know :thumb:
 

wayoflife

Administrator
Staff member
IMPORTANT CORRECTION
So, I just got off the phone with Dynatrac and need to make an important correction. The JL Wrangler tube cross section I show in my photos is based on a distributed CAD model but apparently, is not accurate to what is actually being used. Just to make absolutely sure, Dynatrac went out and physically measured the tube on our Rubicon front axle and found that it is 2.75" in diameter BUT, it has a wall thickness that's closer to what you find on the JK Wrangler. To be exact, it's even a hair thicker and measures 0.281". Dynatrac then went out and physically measured the Sport and Sahara axles they have and found them to be the same - 2.75" diameter and with a 0.281" wall. Needless to say, the photos I posted are NOT 100% accurate as the JL Wrangler tubes are in fact thicker but still a far cry from a ProRock 44JL.

I apologize for the inaccurate information and I hope to post updated photos in the near future.
 

Dale72

Caught the Bug
well that sucks, I was hoping the axle would be one less future replacement item.

Not that I plan to be doing anything to push it hard enough to break it, but I know I've picked wrong lines or slid in the wrong direction and have taken a hit on the PR44 :doh:

Good to know :thumb:
Yeah makes me want to keep my JKU now and not trade it next year

Sent from my SM-G950U using JL Wrangler Jeep Forum mobile app
 

JTCO

Meme King
Those Dynatrac axles are obviously a lot stronger but how much of a weight penalty do they add?

I don't see that they have specs out yet, but when they did it on the JK, here's the comparison weights that they put out on the housing.

IMG_20190204_164719_188.jpg

Being that the weight is unsprung, it's not going to affect your COG like a big as roof rack or something like that.
 

Rampart22

Member
Soooo am I to assume I’ll be needing an upgrade to my rubicon axles? Sounds like my hemi swap will have to put on hold.

Why can’t/won’t FCA just have this add as an optional factory upgrade from the start.

And why doesn’t Eddie just work with Direct with Jeep to make this right the first time.

Jeep=boat

$$$$$$


Sent from my iPhone using JL Wrangler Jeep Forum mobile app
 

RMC2

Member
Good to know info.

Thinking about the two tube thickness versions of JK Prorock 44’s: How about a prorock 44jl with a little thinner tubes than 1/2” to save weight but still be a lot stronger than a jl “44” axle, like .33” thickness.

Just thinking outloud. Wish I could have opted out of the FAD.
 

wayoflife

Administrator
Staff member
Soooo am I to assume I’ll be needing an upgrade to my rubicon axles? Sounds like my hemi swap will have to put on hold.

Why can’t/won’t FCA just have this add as an optional factory upgrade from the start.

And why doesn’t Eddie just work with Direct with Jeep to make this right the first time.

Jeep=boat

$$$$$$

Not necessarily. As I said, our axle has been holding up in spite of us running 37's, we just want to play harder and have confidence in our axle.

My question is should I upgraded my stock sport axles to the Rubicon 44’s if I wanna run a 37’ tire? $5000 upgrade and chances of me running hard trails like wayalife is slim to none.

For you, I don't think so. What you have should hold up just fine for your needs.

Good to know info.

Thinking about the two tube thickness versions of JK Prorock 44’s: How about a prorock 44jl with a little thinner tubes than 1/2” to save weight but still be a lot stronger than a jl “44” axle, like .33” thickness.

Just thinking outloud. Wish I could have opted out of the FAD.

So far as I know, the PR44JL will only be offered with the larger tube and in a 0.50" wall. While it will be heavier, I don't know if it's enough to really matter especially being that it's unsprung weight.
 

Bsimon187

New member
Eddie- with this axle beefiness and the RCV's are they still saying maxed out at a 37? or did they bump it up to a 40?
 

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