NP231 converting to NP242

[Hayden]

I have a 98 XJ that I am wanting to take original NP231 out of and swap in the NP 242 so that I can have the full time option. I know for the most part it is a direct bolt in. My question is for anyone who has done it, what does it take the change the wireing so the "full time" light will come on? I am trying to make this look as factory as possiable. I know there is a location for the full time light but im not sure if there is actually a bulb in it or not. I would also assume the switch on the T-case uses a different plug for the indicator wires. If anyone has any insight on this I would appericiate any help.


Thanks
Hayden

 

[JLane99XJ]

are you planning on doing a hub conversion?

i don't really understand why anyone would want to do that..

i'll take that 231J off your hands if the price is right, bob

 

[Hayden]

Why would i do a hub conversion? The 242 still has a 2wd option and all the same range selections as the 231 but it also has the option for full time 4wd on the street, good for snow and icy conditions and wet weather. I am tradeing my 231 for the 242.


Hayden

 

[JLane99XJ]

oh i see, my mistake i thought u were talking about the model that came in the grands that was all-time 4wd

 

[xj-grin]

I have a 98 XJ that I am wanting to take original NP231 out of and swap in the NP 242 so that I can have the full time option. I know for the most part it is a direct bolt in. My question is for anyone who has done it, what does it take the change the wireing so the "full time" light will come on? I am trying to make this look as factory as possiable. I know there is a location for the full time light but im not sure if there is actually a bulb in it or not. I would also assume the switch on the T-case uses a different plug for the indicator wires. If anyone has any insight on this I would appericiate any help.


Thanks
Hayden

Hayden,

I contemplated and actually started this swap in my 99, but decided that my 5 speed and stroker would provide a bit too much torque to the 242 for comfort, so I abandoned it. I did at one point have a 242 installed however, so I have a little insight. Make sure the case you pick up has a 23 spline input gear, as that is what your 98 tranny has. I picked up a case for really cheap out of a 90, but then had to swap in a 23 spline gear. While the older cases use a mechanical speedo gear, you can swap your existing 231 gear assembly into the 242 case and make the speedo work, no problem (at least with mine). You will want to pick up a shift gate for your shifter to match the different shift pattern on the 242, as well as a new bezel, but you don't actually need it. As to the full time light, I never got that far, but in asking around I was told that the 99 wiring would light the light, it simply needs a bulb, so I would guess that is all you would need to add too.

If you're interested, I have the t-case I was going to swap for sale, as well as a shift gate I would trade you for yours... PM me if you're interested.

Chris

 

[XgeekstarX]

Hayden,

I contemplated and actually started this swap in my 99, but decided that my 5 speed and stroker would provide a bit too much torque to the 242 for comfort, so I abandoned it.

Chris

last time i checked it was good for 1486ft/lbs.




from 4wheeloffroad.com:

NP242

Type: Part-time/ full-time, aluminum, chaindriven case

Low range: 2.72:1

Applications: ’98-present Dodge Durangos and Dakotas, Hummers, and ’87-present Jeep Cherokees

If you have an NP242 in you truck, keep it! Stop sending us letters asking how you can swap in an NP231 because we don’t want you doing it. The NP242 is a better case and it gives you more choices when it comes to routing power to the wheels. The NP242 HD is stronger than the NP231, and you can get slip-yoke eliminator kits and lower low-range gears for it just like an NP231. If it makes you feel better, take pride in knowing that AM General uses its own version of this case called the “NVG242 HD AMG.” It is rated for the 11,500-pound GVW of the Hummer. Of course it is way cooler than the version in your Cherokee because it has an external transfer case oil cooler. We’ll let you know when we come up with a way to retrofit it to other cases.

 

[XJJack]

I have the 242 in my 98, and I hope it is just adding the bulb because mine dosn't work ether.
Those ratings sound great, but how do I keep from having to change the chain every two years from strech?

 

[88XJ_FireFighter]

I have the 242 in my 88 as well. I was just about ready to swap in a 231 till I found a 242 from another 88. Do the chains on the 242 suck that bad?? Aren't they like $100/pc?? I certainly don't want to have to buy the case for $150 and spend another $100 for a chain.

Sorry for the hijack.

 

[CartsXJ]

I have the 242 in my 88 as well. I was just about ready to swap in a 231 till I found a 242 from another 88. Do the chains on the 242 suck that bad?? Aren't they like $100/pc?? I certainly don't want to have to buy the case for $150 and spend another $100 for a chain.

Sorry for the hijack.

New Chain from the dealer for a 98 242 is $161........and thats at the mechanic's price. I have about 150K on my 242 so I have a few leaks and the mode springs and fork pads are worn, won't stay in 2WD, so order up all new parts from my Jeep mechanic buddy. All for around $220, outer seals, chain, o-rings, springs, the whole-nine. And if I can ever get my hands on a 242HD from the H1, it will definately be retro-fitted in. It even comes with a 32 splined SYE from the factory and with the 32 splined front output and extra wide chain, very beefy chain case. Plus that oil cooler, I could definately use one, its gets hot under there.

 

[Hayden]

Hayden,

I contemplated and actually started this swap in my 99, but decided that my 5 speed and stroker would provide a bit too much torque to the 242 for comfort, so I abandoned it. I did at one point have a 242 installed however, so I have a little insight. Make sure the case you pick up has a 23 spline input gear, as that is what your 98 tranny has. I picked up a case for really cheap out of a 90, but then had to swap in a 23 spline gear. While the older cases use a mechanical speedo gear, you can swap your existing 231 gear assembly into the 242 case and make the speedo work, no problem (at least with mine). You will want to pick up a shift gate for your shifter to match the different shift pattern on the 242, as well as a new bezel, but you don't actually need it. As to the full time light, I never got that far, but in asking around I was told that the 99 wiring would light the light, it simply needs a bulb, so I would guess that is all you would need to add too.

If you're interested, I have the t-case I was going to swap for sale, as well as a shift gate I would trade you for yours... PM me if you're interested.

Chris

Thanks. The 242 i am getting is comming out of a 98XJ also so it wont be a problem with input splines and speedo stuff. I am also going to get the shift gate and bezel from the same jeep because we are installing an atlasII in place of the 242. Now, If i remember correctly the plug on the 231 for the shift light has only 2 pins, I dont think the same harness from my jeep is going to plug into the 242 plug. There inlies the delema.


Hayden

 

[xj-grin]

Thanks. The 242 i am getting is comming out of a 98XJ also so it wont be a problem with input splines and speedo stuff. I am also going to get the shift gate and bezel from the same jeep because we are installing an atlasII in place of the 242. Now, If i remember correctly the plug on the 231 for the shift light has only 2 pins, I dont think the same harness from my jeep is going to plug into the 242 plug. There inlies the delema.


Hayden

Hayden -- I know my harness worked on the 90 case I was using, but can't speak to late model. You should see if you can get the pigtail from the doner vehicle and splice in that harness...

 

[bjoehandley]

I wonder if the 242HD will bolt directly up to the AW4, that would be great for strokers with forced induction and lots of traction.

 

[Cupcake]

this thread has been dead for awhile but i have a few questions if anyone can answer them that would be great. i have a '91 xj with the 231 and i wanted a 242 for the full time 4wd what would i have to do and how can i tell the difference between a np231 and a 242 thanks

 

[XgeekstarX]

this thread has been dead for awhile but i have a few questions if anyone can answer them that would be great. i have a '91 xj with the 231 and i wanted a 242 for the full time 4wd what would i have to do and how can i tell the difference between a np231 and a 242 thanks

there is a metal tag riveted to the back of the case that either says NP231 or NP242. or if you're at the junkyard taking a look at the shift gate for the transfer case before you crawl under there. if it's a 242 it will have these selections.

2wd
4wd part time
4wd full time
neutral
4wd low

 

[Hayden]

And since the thread is going again.......I have looked a little more at my 98 and found that the plugs are different for the sensors between the 231 and the 242. The 242 has a 3 plong plug and the 231 is a 2 prong. Does anyone know if the third wire is burried somewhere in the harness if the jeep came with a 231?


Hayden

 

[Mercenary]

Hayden: Not to dissuade you from your quest to swap in a 242 in place of your 231, but I have to ask...Why?

I have a 242 in my 92. My 91 had a 231. Both have seen plenty of icy and snowy roads and both transfer cases worked just fine. I know the 242 has a couple more features to make it a bit more friendly on the street but it seems to be a big hassle to swap in a 242 for such little return.

Now if you want to run in 4wd in dry roads, then the 242 is your case. That center diff in the 242 will ease some of the burden on your driveline. Not than running in 4wd is a good idea on dry pavement.

 

[semisynth]

Hayden: Not to dissuade you from your quest to swap in a 242 in place of your 231, but I have to ask...Why?

I have a 242 in my 92. My 91 had a 231. Both have seen plenty of icy and snowy roads and both transfer cases worked just fine. I know the 242 has a couple more features to make it a bit more friendly on the street but it seems to be a big hassle to swap in a 242 for such little return.

Now if you want to run in 4wd in dry roads, then the 242 is your case. That center diff in the 242 will ease some of the burden on your driveline. Not than running in 4wd is a good idea on dry pavement.

Since this has little to do with his actual question I'll answer for him. I have a '94 w/a 242 and a 2000 w/a 231 and am swapping in a 242 from a ZJ into it. When the weather gets bad be it snow/ice or heavy rain I would rather be driving my '94 hands down.
If you live in the north east IMHO the 242 is a much better option than the 231 for a daily driver in the winter. In full time you always have traction when you need it and you don't have to constantly be shifting in and out of 4wd on roads with patches of snow/ice separated by patches of relatively dry road (the condition I normally encounter here). It also gives you the option to use 4wd in the rain. I think using full time on dry pavement is a great idea because it handles better in full time especially when you are lifted with larger tires.

 

[Hayden]

Im wanting to do the swap because i just want the ability to run 4wd on the street. For instance, the other day it rained and the rear end of my jeep gets looses very easy. The limited slip is tight. I don't want the binding and the stress of the 231 on the street and I have a guy that will swap me straight up for his 242. Plus, I work at a 4x4 shop so doing the work is no problem, it will be all bolt in stuff minus what it may take to make the full time light come on in the dash.

Hayden

 

[cLAYH]

Here is my experience in converting my '89 XJ from a 5spd/NP231 to a 5spd/NP242 and eventually to a Auto/NP242.

The wiring harness that came with the 5spd does not support the fulltime light, some wire tracing and splicing would need to be done to get it to work. I nver bothered looking into it. When I swapped in the auto I swapped in the wiring harness and it suported the fulltime light, all I had to do was put a bulb in the dash. This makes me think that if you already have an auto you should be able to find the wire for the full-time light and splice the pigtail from your donor vehicle onto it. But your '98 is probably much different from my '89.

I too enjoy my NP242! Great for winter driving and also for those gravel roads on the way to the trail! Keeps the locked backend from kicking out on the corners. I originally swapped mine in because I can easily buy NP242s for $100 with low miles(nobody wants them!). Its cheaper than rebuilding my NP231. Used NP231s run well over $400 if they are in decent shape, $250 if the chain needs replacing. Much more demand for the Np231 from the YJ/TJ crowd drives up the price.

 

[Dr. Dyno]

last time i checked it was good for 1486ft/lbs.

Yes, and that's torque into the input shaft. When mated to the AX15 with its 3.83:1 1st gear ratio and 4.22:1 reverse, that means it'll handle up to 352lbft (1486/4.22) from the crank, making it more than strong enough to handle the torque of a naturally-aspirated stroker.
The NP231 has a higher torque rating giving it an extra margin of safety.