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.
And here you can see where the lower control arms sit in relation to the coils on both axles.
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.
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.
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.
And here's a picture of the sway bar mounts on both axles showing the different locations.
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.
Here are the computer diagrams from Clayton showing the bracket locations and measurements.
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.
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.
And here you can see where the lower control arms sit in relation to the coils on both axles.
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.
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.
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.
And here's a picture of the sway bar mounts on both axles showing the different locations.
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.
Here are the computer diagrams from Clayton showing the bracket locations and measurements.
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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