NP242 Transfer Case Swap?

[jwilkinson01]

again.. unless someone has a 231 and 242 side by side can't really answer that unless you give us something to measure their 242 from that is common between 231 and 242.... like say one of the bolts they mount to rear of trans..

length...... it is reported they are 1" longer to end of rear output shaft but that is an iffy measurment though likely not longer.

this might help. Have no read thru it

[URL]https://www.cherokeeforum.com/f2/np231-vs-np242-mount-height-comparisons-207326/[/URL]

Thank you, I had not found that thread, it provides some useful information, if they are correct and the 242 hangs 3/4 of an inch lower than the 231 we know part of the height difference.

I apologize, I didn't think I was being unclear, length from the mounting surface to the transmission to the end of the rear output shaft as that would be the measurement that will affect the rear driveshaft length.

 

[tjryder]

Hi gents,

I would like to swap NP231 to NP242 in my TJ with NV3550 5 sp box.

Unfortunatley - I managed to get the 21spline version (early years), my box requires 23 spline.

Being in Europe - no easy task to get one...

I could get new input shaft though from RockAuto - but is it swapable to early NP242 TC?

 

[Rickyd]

Hi gents,

I would like to swap NP231 to NP242 in my TJ with NV3550 5 sp box.

Unfortunatley - I managed to get the 21spline version (early years), my box requires 23 spline.

Being in Europe - no easy task to get one...

I could get new input shaft though from RockAuto - but is it swapable to early NP242 TC?

What year 242? Around 95-96 the gear teeth were redesigned. So the new input needs to be early or late type depending on your np242. Many np transfercase inputs will swap in

 

[tjryder]

Being 21 spline - it must be pre 1991.

It i berried in a botom of a pallete box as wrong purchase... It has lately came to my mind that maybe I could do just an input shaft swap. That's why I ask...

Any indication of what I should pay attention to identify possibility to swap?

 

[JP_in_STL]

The easiest NP242 to swap into our Wranglers (from my research) is the 97-2001 XJ Cherokee AND the 94-98 ZJ Grand cherokee. These are US Models, not sure on years and crossover in Europe? This is because of the input splines count, and the mechanical drive for the speedometer. Later WJ/WK grand Cherokee NP242 do not have the mechanical speedometer. Later KJ Liberty have the wrong spline count and no mechanical speedo. From my understanding the more common NP231 also share the same input. It may be easier/cheaper to remove/swap with the current NP231 Input Shaft in your Jeep. Or source the more common 231 case from over there?

This is a good resource for swap info: https://www.novak-adapt.com/knowledge/transfer-cases/np242/

 

[Rickyd]

Being 21 spline - it must be pre 1991.

It i berried in a botom of a pallete box as wrong purchase... It has lately came to my mind that maybe I could do just an input shaft swap. That's why I ask...

Any indication of what I should pay attention to identify possibility to swap?

I don't know if thats true. But IF it is pre 95 then get a pre 95 input with the right spline count and install it. One style has rounded teeth ends and the other is sharper.sorry i don't remember which is which

 

[tjryder]

I have a 2000 TJ 5 sp. manual 4.0 with NV BOX and NP231 case.

I used to have and sold 1990 4.0 Auto XJ. With a NP242. I simply loved it on a wet road. Monster ;-)

Now I am building a stroker, have a spare box and want to set it ready to drop in with 242 tc. Power is nothing without control

But - not easy to get those 23 spline NP242 over here. Rare and collectible so not many end up scrapped. Even rolled over disasters get repaired...

Most viable option seem to be just to swap input shaft. If possible.

 

[tjryder]

I don't know if thats true. But IF it is pre 95 then get a pre 95 input with the right spline count and install it. One style has rounded teeth ends and the other is sharper.sorry i don't remember which is which

So - if i open it - i will see those rounded / sharp teeth I guess.

Need to go digging the tc out of the box tomorrow

 

[Coachgeo]

what has folk with this swap done for front Yoke? TJ front yoke I hear will NOT fit the 242. Ive not found any info yet on front yoke spline count. Here are the Yoke part numbers from Crown Automotive 2010 catalog. @007 Catalog shows same part #'s. Still I think is a bit in how it list a few things. Like the WJ with 242 is not in the catalog at all (mine is from an 04 WJ). And it shows X J / ZJ ... it says stopped manufacture in O1 . butthis all I got so far to go buy.

NPxxx / FY= Front Yoke / Part# / notes
228- & 29 FY 4856142 (XJ ZJ)
242 FY 4798138 (xj ZJ)
231 FY 4798120 (TJ XJ ZJ)

 

[Coachgeo]

The easiest NP242 to swap into our Wranglers (from my research) is the 97-2001 XJ Cherokee AND the 94-98 ZJ Grand cherokee. These are US Models, not sure on years and crossover in Europe? This is because of the input splines count, and the mechanical drive for the speedometer. Later WJ/WK grand Cherokee NP242 do not have the mechanical speedometer. Later KJ Liberty have the wrong spline count and no mechanical speedo. From my understanding the more common NP231 also share the same input. It may be easier/cheaper to remove/swap with the current NP231 Input Shaft in your Jeep. Or source the more common 231 case from over there?

This is a good resource for swap info: https://www.novak-adapt.com/knowledge/transfer-cases/np242/

if your going to Autotrans in the swap the NP242 swap as is, mates. If your going to 5speed you need the trans input shaft from inside the the 231 that use to go there.. transplanted into your 242. Pretty sure the rear out put spline mates with your rear drive shaft... but you may have to shorten it... bettery yet to Double cargden while your doing any shaft changes.. maybe even go Hack-n-Tap unless you can afford the very pricey SYE 242 kit.. The front shaft output's spline does NOT mate to anything TJ.... its larger shaft and spline. 32spline? So your going to be re-doing your front driveshaft no matter what... Though it mayyyy just be a ujoint switch if your 242 has that type yoke on it. The flat round yoke needs the cherokee type end on the driveshaft.... though many cherokee users get rid of that Rzepa and swap to a more common Ujoint type with matching yoke.

 

[Coachgeo]

what has folk with this swap done for front Yoke? TJ front yoke I hear will NOT fit the 242. Ive not found any info yet on front yoke spline count. Here are the Yoke part numbers from Crown Automotive 2010 catalog. @007 Catalog shows same part #'s. Still I think is a bit in how it list a few things. Like the WJ with 242 is not in the catalog at all (mine is from an 04 WJ). And it shows X J / ZJ ... it says stopped manufacture in O1 . butthis all I got so far to go buy.

NPxxx / FY= Front Yoke / Part# / notes
228- & 29 FY 4856142 (XJ ZJ)
242 FY 4798138 (xj ZJ)
231 FY 4798120 (TJ XJ ZJ)

from what I am understanding at moment.... is the front output to front driveline is a larger shaft in 242 and more splines (32 spline) compared to the TJ.

 

[Coachgeo]

just for recording purposes.... if you want to utilize any wiring in the TJ that turns on dash lights to tell you what Tcase mode your in (or want to make your own) here is some info.

"...... The 231 dash light switch works differently than the 242. 231 has power and ground wires. When in part time mode, switch is tied to ground via the wires, to make the part time light go on.
The 242 uses transfer case as ground. Red wire goes to part time, and yellow/green wire goes to full time light. Part time ties switch to case ground on red wire. full time ties switch to case ground for yellow/green wire
What I plan to do is cut the black wire; then run yellow/green wire up same path to engine compartment , find the wire to splice it into at dash harness, and splice it. Will pass on info when I have exact info on where to splice.
You could also grab 242 dash wire harness, but would still wind up needing to do splice to bypass the ground and connect to full time. "

 

[Coachgeo]

Agreed the KJ 242 could work, but it will not work with the Tom Woods Slip Yoke Eliminator as that will not work with a 32 spline output. There are other SYEs that will work with the 32 spline output, but if you want to use the mechanical speedo gear they will not work with that. When using an SYE you need a CV driveshaft, so there will be the additional cost of a new driveshaft anyway.

So, if you require an SYE, due to lift height or a raised transfer case and want to retain the transfer case mounted speedo sensor then the KJ is not an option, at least not without an unreasonable amount of work that would easily be avoided by using a 242 from a different donor vehicle..

IF KJ is 32 rear output spline... that is essentially a HD SYE already done for you at factory it sounds like.. The spendy Tom Woods SYE upgrade moves to 32 spline.... in the rear.of TCase also.. I dont know anything about length differences in tail housing though... and There would be speedo differences.

I think I saw somewhere KJ went to smaller shaft diameter and less splines on front output to yoke for fron drive line on the 242 .. so that may fit your 231 case's front yoke if you need it to mate to a TJ driveline. Just speculation though. The other 242's after 1991?? on have a 32 spline heavy duty Front output shaft and yoke but NOT the heavy duty 32 spline @ rear. exept the rare heavy duty ones with 32 front and rear. So KJ is an opposite oddball to most of them.

The best 242 shaft-strength wise has thicker shafts wit 32 spline on front AND rear outputs to drive line yokes.

 

[jwilkinson01]

@Coachgeo what did you ever come up with on the front yoke on the 242? I’m just now getting back to mine and I pulled out the old front driveshaft that I removed from my TJ that was bolted to the 231 and I have got the front yoke off of the 242 and they look like they’re going to match up perfectly

 

[Coachgeo]

@Coachgeo what did you ever come up with on the front yoke on the 242? I’m just now getting back to mine and I pulled out the old front driveshaft that I removed from my TJ that was bolted to the 231 and I have got the front yoke off of the 242 and they look like they’re going to match up perfectly

View attachment 553249

the front yoke used on the 242 varied to what vehicle manufacture it was used in... and/or year. Mine was off a Cherokee 2003? or 04 and used the Rzeppa style yoke.. (see picture) Others are like the one you show here.. which I went out and purchased that kind of yoke used the other day of an older 242... the secret is proper spline count and that the yoke is specified for the 1310 style ujoint if you want to stick with the stock front driveshaft... which is what looks to be both our plans.

what year and vehicle did your NP242 come off of?

 

[jwilkinson01]

the front yoke used on the 242 varied to what vehicle manufacture it was used in... and/or year. Mine was off a Cherokee 2003? or 04 and used the Rzeppa style yoke.. (see picture) Others are like the one you show here.. which I went out and purchased that kind of yoke used the other day of an older 242... the secret is proper spline count and that the yoke is specified for the 1310 style ujoint if you want to stick with the stock front driveshaft... which is what looks to be both our plans.

what year and vehicle did your NP242 come off of?


View attachment 553251

I am not sure what year, I bought it from a guy who bought it from a guy. I just made sure it had a place for a speedo gear (which doesn’t really matter now that I am installing an SYE) and the front yoke I wanted

 

[Coachgeo]

I am not sure what year, I bought it from a guy who bought it from a guy. I just made sure it had a place for a speedo gear (which doesn’t really matter now that I am installing an SYE) and the front yoke I wanted

is your Jeep automatic?

 

[jwilkinson01]

No I have the 5 speed

is your Jeep automatic?

Nope 3550

 

[Rickyd]

No I have the 5 speed

Nope 3550

Have you used the awd yet? If so how is it on highway,in the snow,etc?

I like the idea of a 242 and lots of horsepower

 

[Coachgeo]

No I have the 5 speed

Nope 3550

NP242 likely will not fit direct your 3550. It likely came off an Automatic trans.

Iffff.... you got 231 that came off of the 3550 then you can use a part from it to set up your 242 to fit the 3550 MAYBE....

1. . count splines.. make sure spline counts match transmission. Older 242/231 etc.. had less splines. no match?? no moving forward.
2. compare years.. or dissasemble and measure bearing.. different years (older newer) have different widht bearing... which effects ability to use part of your 231 to convert 242 to fit an standard transmission. If your 231 and 232 match in bearing width your good move on to the alphabet below.... All above is info spread out inside this thread with better details.


- change out the trans input shaft gear inside the 242 to the longer shoulder one that mates to a standard trans. here you got choices in the A's and B's
A. You can take it out of your 231 and put it in your 242 then sell 231 for parts or
A.2- swap input shafts between them; putting one from 242 inside 231.... then you sell the 231 as a Tcase that setup to mate with an automatic Jeep transmissions.

B.1 buy a used Tcase input shaft for a standard and remove one from 242 /install one bought in its place.
B.2- if you have a 231 this Leave's the 231 intact... which you can sell as one for mating to standard trans like it came off of

if the 231 came off an automatic.... then A's are not an option. B.2.. you sell as one to mate to automatics

All above is also spread out in this thread with greater detail.