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

WJCO

Meme King
While this swap has been done before, it's not a direct swap and I will be doing mine soon. It has required a lot of leg work and research finding out what works and doesn't work. I really want this info out there for anyone else doing the swap hoping that it can help out someone else. The trickiest part is that the coil spring mounts were not available for a long time and the JK coil mounts and WJ mounts sit in completely different locations. They currently are available through Clayton Offroad and I believe they are the only company that currently makes them. The other option would be to cut the coil mounts off the existing WJ30 axle and re weld them on the JK44 axle. I decided since I was spending the money to do this swap, that I would go with Dynatrac as they make the strongest housing for something like this and have a great reputation for product quality and customer support. Originally, Dynatrac told me they wouldn't be able to do it due to not being able to get ahold of the coil spring brackets (this was before either Dynatrac or myself knew they were available). I got ahold of ECGS who is the only company that has a Rubicon axle ready to install for the WJ, but sadly they said they would not do a Dynatrac housing. Again, I really wanted the Dynatrac housing since I would already be spending a decent chunk of change. I then decided that I would buy the housing from Dynatrac and do it myself, but shortly afterward found out that Clayton makes the brackets. So I contacted Dynatrac with the product info and specs, and Dynatrac was more than happy to help. So they are currently building my axle. They are building a complete JK axle with ball joints, brakes, knuckles, unit bearings. The only thing that will be different is the WJ Clayton brackets being installed on their housing.

So I'll start this thread by showing the differences between the axles and what will need to be modified. This is a work in progress, so I will probably learn much more once I have the axle and start installing it. Again, I really hope this can help someone who wants to do this swap. So far, the things that are completely different are the knuckles, the coil mount locations, the sway bar link locations, the brake hoses, the abs sensors, the steering linkage, the track bar location, and the bump stops. Also, the axle on the JK is approximately 1.5 inches wider than the WJ.

The upper control arm mounts on the axle can be re-used. They are within .250 of each other comparing the WJ and JK but I know of two builds that said they did not have to modify those. The JK uses larger diameter bolts though, so I will have to change that. It appears the lower control arm brackets on the axle are nearly the same too, they measure the same location between the JK and WJ but I haven't measured the bushing width or bolt size.

The following photos show an example of parts on a WJ axle and on a JK axle.


Here you can see the difference in distance between the coil spring mounts and the pumpkins. You can also see that on the WJ, the coil spring mounts do not sit centered on the tube, they sit forward just a little bit in relation to the centerline on the axle tube. Whereas the JK coil mounts are centered right on top of the axle tube.

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And here you can see where the lower control arms sit in relation to the coils on both axles.

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In this photo, you can see a large difference in the lower track bar mount. On the WJ, it is in a fixed location that cannot be adjusted as it sits under the coil and cannot be moved up. Whereas on a JK axle, it is off to the side and aftermarket brackets can be added as needed. The JK model gives many more options for proper steering geometry after lifting. My WJ current has a 4 inch lift. The axle swap will have Rancho Histeer Knuckles (so the drag link will be flipped) and I will be raising the track bar significantly to match the drag link angle.

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Steering will be the most custom part of my build. The WJ and JK drag links are different in many ways. It's hard to see in the photos, but the tapered studs on the JK and WJ ends are different sized angles and different thread diameters on the ends of the studs. As well as the end link threads where they go into the adjustment sleeve are completely different. To add to that, both the WJ and JK use a 3-piece drag link, but the JK has a longer lower link end and a shorter adjustment sleeve, whereas the WJ uses a really long adjustment sleeve and short link ends. Surprisingly, both are right about 41 inches from pivot point to pivot point. I will most likely contact a machine shop. The pitman arm on the WJ is already pretty tiny and I do not want to ream it. I will be re-using the pitman arm with no modification to it most likely.

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The next difference is the pumpkin itself. The WJ uses a low-pinion Dana 30 and the JK uses a high-pinion Dana 44. The front drive shaft may interfere with the exhaust, etc. I'll have to get the axle installed to really look at it and I may just go heavy on the bump stops if it hits. We'll cross that bridge when we get there.

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And here's a picture of the sway bar mounts on both axles showing the different locations.

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And a picture of the upper mounts on both axles showing that they're nearly in identical locations and should be able to be re-used with no modification.

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Here are the computer diagrams from Clayton showing the bracket locations and measurements.

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I have also already ordered some custom brake hoses to make the swap. I also ordered some JK ABS wheel speed sensors and from what it appears, I can splice them into the WJ sensors and the computer will recognize the JK sensor as one of its own. UPDATE SINCE INSTALL: ABS works! I spliced the black wires together and then the other two together. Tried some panic stops and it works. :thumb: . Bump stops will be a working project once the axle is installed.
 
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benatc1

Hooked
Man thats going to be a lot of work, but youll be very happy in the end im sure. I know I love my PR44 and so will you!!
 

WJCO

Meme King
So I think I have the steering figured out. I went with a Synergy draglink. I've talked to a machine shop and they think they can cut it down shorter and drill and thread the rod to fit the WJ upper end link.

So from this:


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To this:

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WJCO

Meme King
Steering came out perfect. The Synergy draglink modified worked out great. And for any of you wondering what a cut Synergy drag link looks like inside, it's pure thick steel.

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Now for the specs. I took all pieces into the machine shop and had them build it so that the total length from pivot point to pivot point was 41 inches. This is with about an inch or so of adjustment sticking out on each side for fine tuning. The upper end of the DL had to be cut and drilled and threaded with a rare tap. The tap is a 24mm x 1.5 LEFT HANDED thread. Machine shop did get ahold of one somewhere(and let me keep it since I paid for it). This is the thread spec for the upper draglink on the WJ. The jam nut is the same thread specs and I believe only can be obtained through JKS. I bought a few of them just in case I needed to do anything else custom in the future.

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Obviously, I'll have to fit it once the axle is under the Jeep, but this is exactly what I wanted. This will be a fully adjustable drag link with replaceable ends if ever needed.

UPDATE SINCE INSTALL: Drag link appears to be working OK :thumb:
 
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jeeeep

Hooked
wow..that's cool of Dynatrac to use the Clayton brackets, how long before you receive the axle?

I always wondered if Synergy bars were solid, I assumed they were but still wondered.
 

WJCO

Meme King
wow..that's cool of Dynatrac to use the Clayton brackets, how long before you receive the axle?

I always wondered if Synergy bars were solid, I assumed they were but still wondered.

It really was cool that Dynatrac was willing to do that for me. I'm hoping to have it soon. End of last week, I was told they were finishing up the wheel ends. And, yes, that Synergy bar is solid all the way through. Heavy too, when you compare it to OEM.
 

WJCO

Meme King
Axle arrived today and I installed all the steering parts on it. It appears the drag link will work great. I went with hi steer Rancho knuckles and the Synergy tapered joint fit in fine. I also installed the JKS Disconnect lower links, the lower Mopar coil insulators, and tightened a few things up.

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I did have to get new upper arm mount bolts, the JK ones are slightly bigger. I went with an M12 X 80.

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2 issues I already see. 1 is that the track bar bracket is drilled out larger to a 9/16" bore and the OEM WJ bolt is a M12. I likely will weld and re-drill them or add some thick M12 washers and weld those on. I don't want to drill out the existing track bar bushing, it's been fine.

UPDATE SINCE INSTALL: I used the second hole down from the top of the track bar bracket. I welded on 12mm washers on front and back and it worked fine. I purchased longer grade 10 bolts too.

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The other issue was that the Clayton steering stabilizer mount bracket was hitting the tie rod. I couldn't figure out why, being that the Clayton kit was designed around a high steer system. The only thing I can think of, is that it was designed for OEM knuckles with a drag link flip kit opposed to aftermarket hi steer knuckles. On both the Rancho and Reid knuckles, the cast tie rod part raises the tie rod about an inch. So I'm thinking that may be the issue. Either way, it's been cut off and I'll deal with it towards the end of the install.

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EDIT: ^ This is what happened. The photo from Clayton's website shows that they used an OEM JK knuckle with a flip insert which leaves the tie rod in the oem location. My tie rod is an inch higher with the Rancho knuckles and hits on the SS bracket. Likely I will just make a new one and weld it an inch higher.


From Clayton:
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UPDATE SINCE INSTALL: The Clayton lower control arm brackets were drilled for 9/16" bolts. Stock bolts are 14mm. Those 2 measurements are so close that I just re-used the stock bolts. Otherwise I would have had to drill out the bushing sleeve slightly. 9/16" is barely larger than 14mm.
 
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WJCO

Meme King
The more I research the ABS, the more it looks like I will have to go without ABS. If I were to swap both front and rear axles into the WJ, it would work fine, but by just doing front, it may not work. The JK and WJ ABS tone rings have a different tooth count.

Either way, I disconnected both front sensors on the WJ and went for a drive. The ABS light was on, however the speedometer and cruise control still work. I may just stick with this, as it's not a daily driver.

UPDATE SINCE INSTALL: ABS works! I spliced the black wires together and then the other two together. Tried some panic stops and it works. :thumb: .
 
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WJCO

Meme King
I've already anticipated cutting my track bar and then sleeving it and welding it because of the drag link flip. I'm running a Zone track bar that came with my 4 inch lift. But, I just found out that this track bar was made for a JK or a WJ and will fit both vehicles stock or up to 4 inches of lift. So I may not need to do anything it and for anyone doing this with a stock track bar, it may work just fine. I will say that the Clayton track bar bracket does relocate the lower mount about 2 inches toward the driver's side. The upper mounts on both the JK and the WJ appear to be in the same spot. I will post more on this once I'm sure.

UPDATE SINCE INSTALL: Track bar needed to be shortened about 5 inches.
 
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USMC Wrangler

New member
Good thing you have a JK in the driveway to compare to [emoji106]

°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°
http://wayalife.com/showthread.php?p=621404


Ha ha! I've been thinking the same...it was the real justification for the addition of the JKU. [emoji23]


.......................................................................
Overall "build thread"
http://wayalife.com/showthread.php?26097-I-guess-it-s-the-quot-Super-Stocker-quot-build

DIY trail/tube door build http://wayalife.com/showthread.php?24449-My-DIY-Doors
 

WJCO

Meme King
So, the research I did originally showed that if both front and rear axles do not have the same amount of teeth on the ABS toner rings that the computer will sense a slippage and turn on the ABS light and/or force the ABS to engage. I was going to scrap the ABS altogether, however, an old forum post elsewhere from someone who talked to IRO (who has done the swap) said the teeth count DOESN'T matter. According to his post, IRO told him that as long as the speed of any of the toner wheels is constant and uninterrupted, the module won't know the difference. So I figured what the hell, I'll try it. It's worth a try. If it doesn't work, then it's not a big deal.

UPDATE SINCE INSTALL: ABS works! I spliced the black wires together and then the other two together. Tried some panic stops and it works. :thumb: .

So today I wired up the ABS sensors to make sure they're ready. I cut off the WJ sensor ends from the WJ and then cut the JK sensor ends off the new sensors on the axle. I then spliced the WJ sensor ends on to the JK speed sensors. There are only two wires on each. The JK has black and white, and the WJ has black and brown. There was really no easy way to determine which was signal in or out, so I just guessed. I spliced the black with the black and spliced the brown with the white.

UPDATE SINCE INSTALL: ABS works! I spliced the black wires together and then the other two together. Tried some panic stops and it works. :thumb: .

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WJCO

Meme King
It's still in the crate??? Lol! That would kill me, but I can be impatient at times.


.......................................................................
Overall "build thread"
http://wayalife.com/showthread.php?26097-I-guess-it-s-the-quot-Super-Stocker-quot-build

DIY trail/tube door build http://wayalife.com/showthread.php?24449-My-DIY-Doors

Yes, sadly.... if you see post 11 though, you'll see that Dynatrac cuts saddles out of the crate, so it sits there very well. I was going to move it to jack stands, but the crate seems more stable. Plus, it is really HEAVY. The FedEx guy said the total weight including crate is 450 pounds!
 
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