JK Front Dana 44 Rubicon axle into a WJ (99-04), ProRock 44 Swap

Driver's side bump stop done. Moving it to the left about half an inch worked. It clears everything, hits where I want it to, and I didn't have to mess with the control arm bolt.

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I had to cut the rubber a little to fit over where the bolt is now.

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Here's how it sits at ride height and when wheel is starting to stuff.

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Thanks for answering some of the questions I had about this swap with your thread. Also, thanks for getting it done super quick. :clap2:

One of the questions I asked the guy in Texas who swapped in a JK front axle was if instead of messing with the WJ spring perches on a JK axle if it might be possible to make an adaptor for the TOP of the springs and leave the area at the BOTTOM of the springs alone. From what I understand, the JK spring not only sit centered on the axle but about an inch lower than the WJ perches. An inch sounds like plenty of room for a top of the spring adaptor.

I found another thread where the guy left the JK perches and just let the springs angle inward like this / \ . From what I read, he didn't have any problem with it. Is the difference in width between the WJ and JK spring perches the same as the difference in width between the WJ WMS and JK WMS?

What would you do differently if you had it all to do over again?
 
aspera said:
Thanks for answering some of the questions I had about this swap with your thread. Also, thanks for getting it done super quick. :clap2:
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Welcome to Wayalife. Glad to help, I too had a lot of questions before doing this. Keep in mind that any measurements I provide are general and may not be accurate as I'm using a measuring tape in my garage.

aspera said:
One of the questions I asked the guy in Texas who swapped in a JK front axle was if instead of messing with the WJ spring perches on a JK axle if it might be possible to make an adapter for the TOP of the springs and leave the area at the BOTTOM of the springs alone. From what I understand, the JK spring not only sit centered on the axle but about an inch lower than the WJ perches. An inch sounds like plenty of room for a top of the spring adapter.
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Just measuring here this morning, it does appear the JK spring sits an inch lower. The WJ uses a lower rubber isolator where the JK does not. I kept that in mind with the measurement. Something to keep in mind if making your own is that the WJ coil sitting surface extends about 5 inches out from the center of the axle tube. The center of the coil mount extends about 1.75 toward of the center of the axle tube. You also will have to do something with your sway bar mounts.

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aspera said:
I found another thread where the guy left the JK perches and just let the springs angle inward like this / \ . From what I read, he didn't have any problem with it. Is the difference in width between the WJ and JK spring perches the same as the difference in width between the WJ WMS and JK WMS?
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Not exactly sure what you asking, but the distance between the center of the WJ springs is about 37 inches, and it appears the distance between the center of JK springs is around 41 inches. Not sure what you mean in regards to wheel mounting surface, being the axles are 2 different lengths, all measurements I looked into were measured from the center thrust line outward. Being that the upper control arm mounts were re-used, I used that as a reference point. This may help too (Clayton's WJ bracket kit for a JK axle):

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aspera said:
What would you do differently if you had it all to do over again?
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Research the track bar a little more. I've relooked at every thing, and my track bar needs to come down about an inch on the axle side. This means welding 12mm washers over another hole in the Clayton bracket which is a pain in the ass as the space is limited. I really wish Clayton would have left the bracket holes at an OEM 12mm rather that 9/16". Anyone can drill them out bigger if they wanted to go that route. Or they should have provided a 9/16" track bar with the kit as an option even if it were more money.

I still have the old axle and have a jk jeep. So if you have any other questions, let me know and I'll try and answer them.
 
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I dont have anything constructive to add to the thread. I just wanted to say, EXCELLENT thread!! and a VERY clean install! It is obvious you put a lot of time and effort into the swap, and it really shows! Thank you for sharing all the tech info you did! While I dont own a WJ, it was definitely still interesting to read! :2thumbsup:
 
DWiggles said:
I dont have anything constructive to add to the thread. I just wanted to say, EXCELLENT thread!! and a VERY clean install! It is obvious you put a lot of time and effort into the swap, and it really shows! Thank you for sharing all the tech info you did! While I dont own a WJ, it was definitely still interesting to read! :2thumbsup:
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Thanks. :beer:
 
Got my first opportunity to take this thing out for an extended test drive. Did about 100 miles of driving in the mountains through slush and snow. Axle is fantastic :thumb: . The ProGrip brakes are remarkable, the ProSteer joints are very smooth while steering, and I'm loving the hi steer setup. A much more comfortable Jeep to drive now than prior to the swap. The downside is the axle isn't as pretty anymore.

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WJCO said:
Got my first opportunity to take this thing out for an extended test drive. Did about 100 in the mountains through slush and snow. Axle is fantastic :thumb: . The ProGrip brakes are remarkable, the ProSteer joints are very smooth while steering, and I'm loving the hi steer setup. A much more comfortable Jeep to drive now than prior to the swap. The downside is the axle isn't as pretty anymore.

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You were going a 100mph in the mountains through slush and snow?! Lol.. That's great to here everything is nice and smooth


Sent from my iPhone using WAYALIFE mobile app
 
After getting a little bump steer over a manhole cover a week or so ago, I re-looked at my steering angles. The track bar really needed to come down an inch on the axle side to be a little more parallel. So I welded more washers over the larger bracket holes and lengthened the track bar about 1/4" and put it all back together again . Re-did the string test and they are definitely more parallel. Going for a test drive now.

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So bump steer is gone. Steering angles are done. I've had some flighty steering since I installed the axle. The caster was set at 5 when I put it in. So today I added some which definitely corrected the steering, however the caster is 9.5 now which is too high. I had a little driveline noise when decelerating. So I'm going to drop it down a little tomorrow and retry. Stock WJ caster is 9. The bracket kit recommended 5 or 6. I'm hoping to get it around 7 if possible.
 
I got the caster down to 6.5 but drive line noise is still there. Not as constant, but it is still there and comes and goes. Pinion angle is at 1, so I'm not sure I can do much more.
 
WJCO said:
I got the caster down to 6.5 but drive line noise is still there. Not as constant, but it is still there and comes and goes. Pinion angle is at 1, so I'm not sure I can do much more.
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Found out today that the noise is not related to the driveline angle. So moved caster up to about 7 currently. If I were to redo this swap, I would order the axle with extra built-in caster to optimize everything.
 
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Another update. With the hi-steer setup, the factory stabilizer clamp was hitting the diff cover. I was able to rotate it forward but then the stabilizer bolt would hit the drag link over bumps. So I got the Rock Hard 4x4 tie rod clamp and all clearances are good.

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WJCO said:
I think I got the passenger-side bump stop pad figured out. I'll have to cycle the axle again to be sure. I installed a spacer right behind the track bar bracket, so it leaves about 3 inches of up-travel.

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This bump stop pad didn't work out. It fell off. I'm working on a weld-on solution. If the pad was centered right on the axle, it would have worked fine, but it sits on the back edge and a good hit knocked it off.
 
What are the tangible benefits of making the swap? Asking not knowing the ins and out of all the available axels for the WJ.
 
DVLDOG said:
What are the tangible benefits of making the swap? Asking not knowing the ins and out of all the available axels for the WJ.
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The largest benefit of the D44 axle is having a larger pumpkin and gearset so if you re-gear after larger tires, there is less risk involved in breaking the pinion gear. Along with this is that the JK axle is a reverse cut (high pinion) gear set which is a better setup for a front differential as far as how the gears ride together. The stock WJ is a standard cut (low pinion). The other benefit to the 44 axle is the ability to put a locker in with less risk of breaking parts, where as the OEM d30 poses much more risk if you lock it, especially on larger tires.

With that being said, a built 44 axle for a WJ is not cheap, the only company that currently makes on is ECGS and they use an OEM JK 44 axle and put a bracket kit on it. A Dynatrac ProRock44 is a whole different ball game. Thicker tubes, bigger end forgings, patented low clearance housing, and stronger upper mounts. And the ProRock wasn't much more than the ECGS axle. To me, if I'm already spending a decent chunk of change, why not get the best. Now if you want to do all the work yourself, you can get an OEM JK 44 housing or a ProRock housing and do it a lot cheaper if you weld on the brackets yourself, providing you have the tools and knowledge to set up gears.
 
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So I think I got this bump stop pad fixed. I used a 2.5 inch piece of pipe, and added a large washer on top. Then added a piece of steel to the back side of the axle and connected it to the RF lower control arm bracket. And put the stop pad on that and welded it up. So now the pad rests on the axle tube and the piece of steel I added. Seems like it will work. EDIT SINCE INSTALL: WORKS JUST FINE. LOTS OF MILES ON IT.

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