We have been providing Swap kits to put bigger axles in vehicles for years and the Jeep Wrangler JK is no exception. But what axles should you use and what information on the internet is correct?? We will be putting all of the years of information we have in designing and building our kits right here, including the technical factors that go into the JK due to the advanced electronics of the ABS system.
First up is axle choice. There are many possible donor axles for the swap, but the best solution we have found is 2005+ Ford SuperDuty 60 front and the 1999 - 2007 GM 14 Bolt Rear.
"These axles do not have the same bolt pattern, why not use the matching Sterling Rear Axle" - Yes, we understand this and it is simple. You can use the Sterling Rear, but due to the offset of the pumpkin to the passenger side there is clearance issues. Sure you can buy an aftermarket tank or fuel cell, but with the amount of money and time you will put into that it is easier to have the front unit bearings drilled to 8 on 6.5 Bolt Pattern and get new studs pushed in. We have heard anywhere from $50 - $100 is what most good machine shops charge to do this service.
"Why not the 99 - 04 SuperDuty Axle?" - Nothing against that axle, but the 05+ axles have an easy to adapt tone ring built in that will make your JK computer happy. All it takes is a Dodge Truck ABS sensor that will bolt right in and plug into your JK harness. That makes is easy, plus the these axles are much beefier than the 99 - 04 versions and Reid Racing offers knuckles to make High Steer simple. Keep in mind you can purchase our 99-04 Tone Rings and Unit Bearing Tool or Aftermarket Unit Bearings for the 99 - 04 Axles to get workable tone rings.
"OK, but which rear 14 Bolt Axle will I really need? I have this older 14 Bolt and you say 99 - 07..." - First, you have to use the 14 Bolt with the extra ribbing as shown in the graphic. You can certainly use the drum brake version, but for what we see these axles cost lately you are better off finding one that came with factory disc brakes. You will thank us down the road when you want good dual piston calipers braking and a Parking Brake.
What is important when selecting your axle is the flange to flange distance of 57.72". This is important because the JK Upper Control Arms sit very wide and as you can see use up nearly all of the room on this axle. With that being said if you are using the factory upper control arms the room is very tight and you may have to make some adjustments to be able to use the parking brake, so dry fitment will be key for this reason. You can also move the UCA mounts in a little or do some trimming if you need more clearance. **If you are going to a 3 Link rear then the UCA placement will not be an issue***
"But I still want to use this Sterling axle that matches my front" - No problem, we offer a kit to do this, you will just need to either run a stretch in the rear 2" - 4" or purchase different fuel tank option. There are tanks that fit in the rear like the TJ tanks or you can go with a fuel cell and place it in the rear of the Jeep. Just make sure you get one that will be compliant with all of the evaporative fuel system requirements.
What Kind of suspension do I need to run with these kits?" - You can run nearly any Aftermarket Suspension type you want, including our Front 3 Link Kit, but you need to make sure your front lower control arms have a flex joint on both ends. Due to the push out of the front differential on the SuperDuty axle the front lower control arms will be spread out significantly wider than the factory JK LCA's. This will not affect anything the handling of the vehicle, you just need to have the flex joints to allow the LCA's to be able to mount up correctly.
"What else will I need to complete the swap?" - The list can be small or large depending on what you are looking to do with the Jeep. The simple list is:
- Rebuild Kits
- Wheels/Tires (the 5 Lug JK wheels will no longer work)
- Brake line adaptation
- Parking Brake adaptation
- Front Lower Control Arms with Flex joints
"OK, I think I have the axle choices down. What about my ABS?" - Again, a lot of variations here depending on the axle you selected, but there are 3 rules to follow:
- The JK requires all 4 sensors to read correctly in order for the ABS system to work properly. Yes, you may get away with running 1 or 2, but the system will not run properly.
- All tone rings must have the same tooth count. The JK has 52 teeth from the factory and the SuperDuty axles have 60 teeth.
- If you are using the 60 tooth tone rings you must have a programmer capable of adjusting axle gear ratios. **We will cover this more in detail below***
"I am using an 05+ SuperDuty 60 in front and the 14 Bolt Factory Disc in the rear, what do I need for the ABS?" - For the Front you can use our new Super Bearings Unit Bearings and Dodge ABS Sensors and a 52 tooth ABS Kit. This will match the ABS tooth count to the Factory JK counts and not require additional calculations to the programmer settings. This option is the set it and forget it plan.
Our New Super Unit Bearings are engineered to match the ABS tooth count of the JK, as well as provide dual bolt patterns to accommodate matching the 14 Bolt (8 on 6.5") or Sterling (8 on 170mm) rear axles. Click the image above to see full details on this innovative product designed to make your axle swap even easier.
If you are using factory unit bearings from the 05+ Front axle will need to purchase two(2) of the Dodge ABS Sensors listed below. These will simply bolt into the Ford Axle and plug directly into the JK. Since both the Dodge and JK use a similar Canbus system, the computer will be happy after programming**. For the Rear with the factory unit bearings, you need to choose the 14 Bolt ABS Kit with the 60 tooth tone ring to match the tooth count of the front axle. This is very important or the JK will give a ratio mismatch error and may put itself into limp mode.
**Dodge ABS Sensors – Chrysler P/N 5179958AB, Dorman P/N 970-052, or Airtec P/N 5S8491** - or purchase HERE.
**"I have 60 tooth tone rings, what do I do with my programmer?" -The Factory tone rings on the JK are 52 tooth count, this is is what is being read by the ABS sensors and responded back to the Can-bus control system. While we offer options to duplicate this count, it is possible to make the system happy with the 60 tooth rings as found in the Factory Ford axles.
We suggest as a baseline using this calculation to figure out where to start with your programmer, here are some examples.
52 divided by 60 = 0.8666666666666667 This will be our factor for gear ratio and tire size.
Gear Ratio Calculations:
5.38 x 0.8666666666666667 = 4.66
5.13 x 0.8666666666666667 = 4.45
4.88 x 0.8666666666666667 = 4.23
Tire Size Calculations:
42 x 0.8666666666666667 = 36.40
40 x 0.8666666666666667 = 34.67
37 x 0.8666666666666667 = 32.07
Keep in mind this is a baseline and may vary by actual tire diameter and other factors, so some additional adjustments of the programmer may be required. Not all programmers allow custom gear ratios so it may be necessary to find an options close to your calculation and fine tune with tires size as most programmers allow tire size adjustments to the .1"
"The SuperDuty axle I have is a 99 - 04 version, how do I get the ABS correct?" - For these axles you have a few choices to get the ABS correct, 1 - Purchase our 99-04 Tone Ring and Unit Bearing Tool to replace the 60 tooth ring installed in the 99-04 factory unit bearing, 2 - Place all 4 sensors on the rear axle and route the front wiring harness to the rear wheels or 3. Purchase aftermarket Unit Bearings from Currie or Nitro.
Here is how to set up the 4 Sensor system:
We suggest keeping with the factory tooth count, so choose the 52 tooth option, and purchase a second pair of ABS Mounting Brackets. The system will be installed as in the image below with sensors sitting 180 degrees from each other(Brackets are light gray, sensors are yellow).
"How do the Tone Rings and ABS Mounting Brackets get installed?" - The axle will need to get torn down and the hub assemblies will need to be machined to press on the Tone Rings with Green Loctite as shown. Only machine the ends enough so that the Tone Rings sit flush to the back of the hub as below. **We strongly suggest machining after you receive the tone rings as the inner diameter will vary and a tight press fit is necessary**
Next, the axle flange will need to be notched and the Backing Plate modified to allow the ABS sensor to pass through.
Once all of this complete the unit can go back together and look like this. Make sure the ABS sensor slides in and out easily and there is enough clearance so it does not get bent as this will affect the air gap and cause sensor reading issues.
"I am still having issues with my set up I can not figure it out" - We are always here to help, you can call our Technical Support Team M - F 8:30 am - 5:00 pm MST, email us at [email protected] or hit the contact us page on our website and submit your questions.
For more details on the ABS setup you can read more HERE.
All of our Axle Swap Kits and ABS options can be found HERE.