NP242 Transfer Case Swap?

tagunz

tagunz

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Nov 28, 2019
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Potomac, Maryland
Okay guys, looking to collect the pooled wisdom of those on this forum, as I may be attempting something in possibly unexplored territory.

SKIP TO THIRD PARAGRAPH FOR THE ACTUAL INQUIRY

Backstory:
When I first got my 5spd 2000 TJ Sport about 5 months ago, it had dangerously bald tires but I didn't gaf and took it mudding within the first month of ownership. Ironically, it had no issues while mudding; the real downside was when I was returning home it was pouring and hydroplaning would get so bad in 2WD that when I drove the 2 1/2 hours back on the highway (@75mph average), I left it in 4HI the whole time(yeah, I know, it's not good for the drivetrain- lesson learned). Anyways, I used my 4HI i few more times that week bc of rain/snow sludge etc. and eventually it had either the chain or some other component in the t-case wear or break on me causing a god awful noise to occur when i put it 4hi/4lo and hit the gas in addition to it not working(2wd has been fine).

So once I did some research and was able to definitively identify the t-case as the culprit, I first looked into rebuilding thinking this was the most cost effective route; this was in fact more expensive to buy kit than just outright replacing(even if I did the rebuild myself), so I crossed that option off and looked into buying a used t-case. Because used tj np231j transfer cases from local junkyards in my area are sparse atm- about 150-250 dollars- i tried to find a more cost effective solution, and found that TJ-era XJs use the same transfer case with a longer input shaft. So great, found one near me for $90 with a 6 month warranty and picked it up. Worst case scenario, I would swap the input shafts and call it a day.

Now this is where I get to the interesting part. In my time researching compatible np231 t-cases from other vehicles, I came across a few forum threads stating that in theory, an XJ np242 transfer case could be mated to a tj[Link a/b]. The upside to having a np242 instead of a np231 is that I have the ability to activate full-time 4WD(which means I will basically have AWD) and still retain my full time 2WD capabilities and part time 4HI/4LO including the same 4LO 2.72 to 1 crawl ratio. After asking people on the wranglerforum[Link c] (not the wranglertjforum, just wranglerforum), I was informed that is really was possible(also supported by Novak Conversions as being an "unconfirmed" compatible transmission[Link d]), but I would need to get one off an XJ from the TJ-era (bc of need for speedo gear: not grand-cherokee or a dodge, ONLY cherokee). So my question is, what will i need to make an np242 compatible with my TJ? More importantly, what will I need to get that I won't be able pull out of the np231j currently installed on my TJ?

Also if you are in the tri-state area and have a np242j that fits the above criteria (97-01 cherokee) that you would like to swap for my np231 out of a '99 XJ (not my old broken one but the functioning one from the yard with the 6 month warranty), don't hesitate to post in the thread or dm if you'd prefer.

Thanks for reading. I know it's a long read but I felt it was important to give all the details at once so we could avoid the usual first page of just follow up questions on obviously important details that were not mentioned.

My TJ's Technical Details:
2000 Jeep Wrangler Sport
4.0L I-6
no lift
30X9.5" BFG KO2 AT tires on 15" rims(stock sizing)
stock dana 30s diffs and axles front and rear
NV3550 transmission
np231j transfer case
stock driveline

shoutout to wranglerforum member Digger84. This guy has been a big help in getting answers about what I need to look for when trying the find the right t-case for my specific application. Most of the time he knew what answers I needed before I even asked and has just been an all around good sport about dealing with my dumb questions LOL.

links mentioned:
a: https://bit.ly/2QffMr1
b: https://bit.ly/2ZgHOGB
c: https://bit.ly/35No1Ry
d: https://www.novak-adapt.com/knowledge/transfer-cases/np242/

I also have a YT channel I just started where I will begin posting content on my TJ. I will definitely post a DIY guide for swapping from a np231 to np242, so subscribe if you want to see that:

https://www.youtube.com/channel/UCLt9N5WE_jTaUdcA-EB4Zow
 
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I fixed the links for you. You can see this thread for more info on why those links didn't work: Why are Wrangler Forum and Jeep Forum blocked? The people who run those forums (Vertical Scope) are assholes in every sense of the word.

Thanks for the details. You definitely don't seem to hear too often about people swapping 242 transfer cases into TJs.
 
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Chris said:
I fixed the links for you. You can see this thread for more info on why those links didn't work: Why are Wrangler Forum and Jeep Forum blocked? The people who run those forums (Vertical Scope) are assholes in every sense of the word.

Thanks for the details. You definitely don't seem to hear too often about people swapping 242 transfer cases into TJs.
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thanks chris! read through the thread about those other forums and i definitely resonate with the sentiments from the wranglertjforum's users with people being assholes to newer people on the other sites mentioned.

Either way I posted this pretty late so will be waiting for some responses in the morning LOL

glad to know the mods here are on top of their stuff!
 
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EzPeezy said:
I've read a lot more about people swapping OUT their 242 for a 231. You might be taking a step backwards here.
Click to expand...

I believe the reason swaps from a 242 to a 231j are much more common than the other way around is simply because of larger aftermarket support. there is also a 249 in the zj that people confuse for the 242 that has a viscous coupler with a life span of 150k miles and all-time awd meaning no 4wd hi/lo or 2wd, so when the vc's go bad it's sometimes cheaper to just replace the whole case and since the 231j from a xj is usually cheaper than a 242(which you could only get as an option) and has that extra benefit of high aftermarket support, most go with the 231. but most write ups are actually made to show how to replace the 249 in the zj with the 231 or the 242 interchangeably, so neither one is inherently "better" than the other; it all just depends on your application.
 
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I’ve done the Xj 231 to 242 twice, and I got the drive shaft from the donor rig along with the detent strip which the shift lever has stop positions for, if I recall I think the 242 may be slightly linger then the 231 and you might want a short shaft kit for it (sye)
 
T Crawford said:
I’ve done the Xj 231 to 242 twice, and I got the drive shaft from the donor rig along with the detent strip which the shift lever has stop positions for, if I recall I think the 242 may be slightly linger then the 231 and you might want a short shaft kit for it (sye)
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How do you usually source your 242? do you swap with someone who wants the 231 or just go to a yard?
 
I bought mine off of wrecking yard vehicles, on my wj I found a v8 np242hd from one of the recyclers that had a portland store and they shipped it to my area for pick up. That was lkq
 
I’ve done two xj and one wj, each were from the same line of vehicle, the np242 on the Tj will have to be drilled to clock it appropriately for the tj and you may want a shifter cable like Novak or savvy
 
so I found some at a reasonable price on facebook marketplace, but they are all out of state. anyone have any recommendations on who to ship it through?
 
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