XJ axle swap/build

[DocTremp]

Originally Posted by sdspearo

They are, IF you can find one. I looked for months and couldn't find one before finally succumbing to an Atlas.

Same here, I looked for one for a few months too but either they go super quick or someone wants way too much for it, on the other side of the country. I’m trying to convince my wife a little at a time haha


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[GordoSmasho]

Originally Posted by DocTremp

I want one so bad!


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Its soooo worth it. And its more than just gearing. Your driveshaft lengths will match so you only need one spare. The main section of the tcase will be in the factory location so you dont have to cut up the floor to make it fit. I didnt cut mine at all and it is only 1 inch below the frame rails.

[Rob D]

Originally Posted by DocTremp

Same here, I looked for one for a few months too but either they go super quick or someone wants way too much for it, on the other side of the country. I’m trying to convince my wife a little at a time haha
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I had a 242 in my jeep originally and started having issues. So I looked up the price of a brand new 242 case and convinced my wife the extra $300 (at the time) for the Atlas was a much better choice than another 242 "which would end up giving me the same problems".

[DocTremp]

Originally Posted by GordoSmasho

Its soooo worth it. And its more than just gearing. Your driveshaft lengths will match so you only need one spare. The main section of the tcase will be in the factory location so you dont have to cut up the floor to make it fit. I didnt cut mine at all and it is only 1 inch below the frame rails.

All of that sounds great to me. I’m somewhat concerned since I got the SFR tcase skid and I’m worried it might not fit an Atlas.


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[DocTremp]

Originally Posted by Rob D

I had a 242 in my jeep originally and started having issues. So I looked up the price of a brand new 242 case and convinced my wife the extra $300 (at the time) for the Atlas was a much better choice than another 242 "which would end up giving me the same problems".

That is a pretty genius plan. I’ll see if I can do something similar. I might have to wait as we might be buying a house in the next month or so lol


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[89Mock]

What size output shafts did you go with and what gearing did you pick?

[DocTremp]

Originally Posted by 89Mock

What size output shafts did you go with and what gearing did you pick?

So far I have not made a decision on whether to go atlas or not. I have a roller 04 TJ Rubicon that I am parting out and I am thinking of using the 241OR but I’m having trouble finding a way to hook up the speedo to my Renix Jeep. I’m need to find out if Atlas has a way to use the speedo cable and if so I might sell the 241OR and go atlas. We’ll see. Thanks for checking in, I think I’d do 1310s and 10:1 or 11:1 gearing since I went with 4.56s in the diffs.


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[89Mock]

https://www.advanceadapters.com/prod...-case-builder/

Tech vault
Speedometer Options
Mechanical speedometer housing.

Is the 241OR A 21 or 23 spline?

[DocTremp]

Originally Posted by 89Mock

https://www.advanceadapters.com/prod...-case-builder/

Tech vault
Speedometer Options
Mechanical speedometer housing.

Is the 241OR A 21 or 23 spline?

Thanks! That was super helpful. Looks like atlas might be a better fit.

I believe they’re all 23 spline, at least that’s what I’ve heard.


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[GordoSmasho]

I fully support this. I always suggest getting the 4speed. It will make your front and rear driveshafts the same length so you only need one spare. And the case lands in the same void in the floor as stock so less clearancing is needed.

[XJensen]

I love having the 4 speed. The np231 and 4 speed atlas are about 3/4" different if I recall, I can look through my pics if you need to know for sure.

I went with the 5.44 and I would love to see how the higher ratios. If I am in low low and 1st gear it works great in most cases. The 2:1 works great for the easier stuff and rytted dirt roads and sand.

If I were to do anything different I would do the 4 speed with the 4.3. I am interested to see how much better it is on harder stuff like soup or the optional line on slick rock

[DocTremp]

Originally Posted by GordoSmasho

I fully support this. I always suggest getting the 4speed. It will make your front and rear driveshafts the same length so you only need one spare. And the case lands in the same void in the floor as stock so less clearancing is needed.

That makes things really nice. I have the SFR link mounts and crossmember/tcase skid and it’s set up for the Np231j so I think it will work.


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[DocTremp]

Originally Posted by XJensen

I love having the 4 speed. The np231 and 4 speed atlas are about 3/4" different if I recall, I can look through my pics if you need to know for sure.

I went with the 5.44 and I would love to see how the higher ratios. If I am in low low and 1st gear it works great in most cases. The 2:1 works great for the easier stuff and rytted dirt roads and sand.

If I were to do anything different I would do the 4 speed with the 4.3. I am interested to see how much better it is on harder stuff like soup or the optional line on slick rock

Thanks for the info! That’s not too bad, might be even easier to install than the NP241OR haha!

Yeah, the 4 speed makes so much sense because of how many options you have with the doubler and the front/rear drive options too.


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[DocTremp]

Now I just have to get this thing parted out and sold so I can afford an Atlas maybe



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[89Mock]

Originally Posted by DocTremp

Thanks! That was super helpful. Looks like atlas might be a better fit.

I believe they’re all 23 spline, at least that’s what I’ve heard.


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damn, I'd need a newer transmission. I was interested until it required me getting a new transmission.