NP242 Transfer Case Swap?

FWIW found an input gear on ebay from a 2003 NP231 that is said to mate with NP3550.... aka- likely exactly what is in my 231 already. Will try that to see it will fit in the 242. If so..... most the way there. Hopefully matches the bearing size and gear matting needs. Doing it this way leaves me a 231 to sell with a newly installed SYE.
 
Last edited:
FWIW found an input gear on ebay from a 2003 NP231 that is said to mate with NP3550.... aka- likely exactly what is in my 231 already. Will try that to see it will fit in the 242. If so..... most the way there. Hopefully matches the bearing size and gear matting needs. Doing it this way leaves me a 231 to sell with a newly installed SYE.

What year is your 242?
 
2003 from 6cyl Grand Cherokee.

seems far as I can tell is 95 and up on 242 and 231 they are 16mm bearing..... so ordered a 242 rebuild kit to put in while case is apart.

Are you going to do a SYE on the 242?
 
Are you going to do a SYE on the 242?

no... will Hack-n-Tap.... SYE kit for 242 out of my budget these days.

Doing 242 for slippery highway not offroading. My MB 5cyl diesel in the TJ is torque-y thus will help in many offroad instances... yet not gear busting torque-y. Have found though the diesel swap wants to push my rear out in slippery road conditions more than my past not so stock TJ from years ago. (1997) Snow is likely going to be worse. Spun out once and later Rolled that 97 TJ down a bank 2.75 times on BLack Bear Pass in CA. via that rear end that likes to pass the front (2000). Both times snow/ice conditions.

Not in mood for that again, so now that in a TJ again.... want to limit that potential. Only discovered the 242 option month ago so have jumped on it since whole drive system is out being swapped with refreshed engine. Annnnyway, like then, this is my daily driver / occasional weekend offroader. Now will also be / tag-along behind future live-in Poo Mans LMTV camper. LMTrV??

Might eventually do a 6pin planetary though... (assuming they are same in 242 and others if I get the matching gear/bearing surface* (late vs early) ). Thinking that would be less costly upgrade yet still use my existing Drive Shafts and yokes end up with after the Hack-n-Tap. Would be sorta of a "medium duty" upgrade and not Heavy Duty?? yet no need to change driveshaft and yokes again.

I am curious though if a 231 tail housing will fit the 242 allowing for more shaft cut pre Hack-n-Tap install and give me Speedo too.

*not sure if bearing surface size relates to Planitary too or if that is just Output shaft concern.. I dont think so
 
Last edited:
  • Like
Reactions: tagunz and Wildman
Found this elsewhere... might help someone with speedo and dash stuff

"
For the speedometer gear, I’d just take the entire vehicle speed sensor from your 231 and drop it into the 242. Make sure to take picture of the orientation of the VSS before unbolting it!! Or else you will have to remove and adjust it til you find the right slot for speedometer gear to engage with the drive shaft .

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." (from https://www.cherokeetalk.com/threads/np231-to-np242-swap.75596/ )
 
Found this elsewhere... might help someone with speedo and dash stuff

"
For the speedometer gear, I’d just take the entire vehicle speed sensor from your 231 and drop it into the 242. Make sure to take picture of the orientation of the VSS before unbolting it!! Or else you will have to remove and adjust it til you find the right slot for speedometer gear to engage with the drive shaft .

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." (from https://www.cherokeetalk.com/threads/np231-to-np242-swap.75596/ )

I believe the hole for the vss sensor hole is not drilled out on the ZJ np242 because the sensor is in the transmission, so this only applies to an XJ np242.

This thread has someone who did an np242 swap in his np249 ZJ and ran into this issue.

If you could find the tail cone off of an XJ np242 then you could remedy this, but a plug-and-play option with the factory sensor doesn't seem feasible without taking it apart.
 
I believe the hole for the vss sensor hole is not drilled out on the ZJ np242 because the sensor is in the transmission, so this only applies to an XJ np242.

This thread has someone who did an np242 swap in his np249 ZJ and ran into this issue.

If you could find the tail cone off of an XJ np242 then you could remedy this, but a plug-and-play option with the factory sensor doesn't seem feasible without taking it apart.

Im wondering if the 231 tail housing is not usable on 242's. though not sure the speedo hole would line up where the part of the 242 output shaft a speedo ring would go for zj.

Read somewhere that the weakness on 231 and other NP output shafts was where the speedo goes. Being 231 was in the list then sounds like this break point would be on T-Cases that; like 231, had speedo set up to align with the hole for speedo spot on rear tail bearing housing. Part of my wonders if NPG moved the speedo to a different type of sensor and location on other T-cases so they could negate that weak spot by skipping milling the shaft for it. Net result gaining stronger shaft, with out having to go to a thicker diamter $haft.
 
Last edited:
Regarding cross-compatible tailhousing swaps, I think the shafts have different bearings between the np231 and np242 based on the rebuild kits.

It may be worth the effort to call one of those online salvage jeep part out companies to source a tailhousing. i know at least dex jeeps has a seemingly endless supply of XJ's, and shipping just a tailhousing should be relatively inexpensive.
 
  • Like
Reactions: Wildman
Regarding cross-compatible tailhousing swaps, I think the shafts have different bearings between the np231 and np242 based on the rebuild kits.

It may be worth the effort to call one of those online salvage jeep part out companies to source a tailhousing. i know at least dex jeeps has a seemingly endless supply of XJ's, and shipping just a tailhousing should be relatively inexpensive.

output bearing and seal on both housings appear to be the same which is what lead me to go hmmmm??? in the first place... that and have got an SYE kit I can put in 231 that came out..... thought is rebuild it with SYE to sell it.... and that would leave the 231 housing left over to put on the 242

https://www.transmissionpartsdistri...2-dodge-ram-2500-3500-02-07-liberty-bb1-1015/
https://cobratransmission.com/np-23...JabDTp5hHlmWcA4BN8Q2Up6f4FXqDW6AE1-BlsJMc5E48
 
output bearing and seal on both housings appear to be the same which is what lead me to go hmmmm??? in the first place... that and have got an SYE kit I can put in 231 that came out..... thought is rebuild it with SYE to sell it.... and that would leave the 231 housing left over to put on the 242

I found conflicting information online regarding cross-compatibility, but cobra transmissions sells all the tailhousings for the np242 over several years, including casting numbers in the description. If you can identify the casting number on your np231 tailhousing (specifically the tailhousing casting # because each case half has it own casting number), you can cross-reference it with all the np242 tailhousings listed on the site and see if any match. If they do, you should be good to swap.
 
  • Like
Reactions: Coachgeo
This is a long very valuable thread..... getting jumbled though thus to help organize/avoid complicating this thread further- started a supplemental thread specific to another aspect of swapping in a 242- the shift mechanism. There is some info on pages 2 and 3 in this thread but they are pretty specific to using parts pulled from other vehicles. Below thread more specific to using a NP231/242 cable and rest being modded, TJ parts only. Here is the link. Look forward to ya'lls input.

https://wranglertjforum.com/threads...linkage-mods-needed-using-cable-system.75023/
 
Last edited:
Some thoughts on parts for rebuilding the 242 to last a lifetime when one is already approaching old fart status. (aka- not very long in the scheme of things realistically) Curious your thoughts

. used 231 trans input get to fit your transmission (and 242 type gear and bearing size) as a single part so you don't have steal one from your 231. Seems Part #'s are same for 242. Leaves you a . . 231 to sell complete.!!
. oil pump
. bearing rebuild kit
. chain
. used/good 6 gear planetary from larger truck with 242 for added strength.
. hack-n-tap at low buck end or SYE at larger pocket end
. used shift plate minimum..... whole shifter better from an XJ w/242
 
Last edited:
lol... read so many and watched enough videos to have confused myself so far LOL

I've been there.. I know you want to just get it done but you may need to wait until you have it all in front of you. Once the transfer case is installed you can verify.
 
  • Like
Reactions: Coachgeo