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np231 - np242 swap - 98 xj

B

blistovmhz

NAXJA Forum User
Location
Vancouver, BC
I've got a 98 XJ with AX15 and NP231 (with SYE).
My 231 feels sloppy so I figure I'd take the opportunity to swap over to a 242.

Couple questions.

1. What year 242's will work with my 98 XJ? I know I should have a 23 spline input on my 231. If the 242 is 21spline, can I just swap the 231 23spline input onto the 242 and call it a day?
2. Are there any other differences between t-case year's to watch for for this swap?
3. Assuming I've got a full (working but hurting) 231 for parts, can I assume any 242 will eventually fit?
4. Can I take my SYE output shaft from my 231 and swap it onto any 242?
 
96-01 direct swap.
earlier years have different VSS sensor IIRC
You can swap the input shaft
THe tailcone on early t-cases are different and do not have electrical connectors.
 
No you can't just swap your SYE over. That being said, the fulltime option is nice but in my opinion it would be a step backwards if you already have a 231 with an SYE. Spend the money you would put into a swap and rebuild your 231. They are extremly simple on the inside.
 
go1lum said:
No you can't just swap your SYE over. That being said, the fulltime option is nice but in my opinion it would be a step backwards if you already have a 231 with an SYE. Spend the money you would put into a swap and rebuild your 231. They are extremly simple on the inside.
Click to expand...

I thought the 242 was supposed to be a little more robust/duable as well isn't it?
The 231 rebuild option is still on the table. The issue is that this is my DL and I'm not entirely sure what parts I'll need for the rebuild till I get the thing apart, at which point I'm outta wheelz till it's all put back together again. Other issue is that I'm pretty much XXXXed for shop space and will be working outta my living room right now :)

Is the 242 really not worth it? I've been pretty cheap in the past with parts for my Jeep, but at this point I just want a solid driveline again and this slop is killing me.
 
The 231/242 debate will never end, but there's only a slight difference in strength (231 being stronger). I'm a 242 fan, but for your money, I agree with go1lum, spend the money on a re-build kit (it comes with all the rebuidable parts) and re-build your 231 w/SYE. Don't tear it apart, then try to only find the parts you THINK need replacing. I'm not sure what "slop" you're referring to, but it's probably nothing more than a bad chain. You can replace the chain while the TC is still in the rig.
 
Flyfisher said:
The 231/242 debate will never end, but there's only a slight difference in strength (231 being stronger). I'm a 242 fan, but for your money, I agree with go1lum, spend the money on a re-build kit (it comes with all the rebuidable parts) and re-build your 231 w/SYE. Don't tear it apart, then try to only find the parts you THINK need replacing. I'm not sure what "slop" you're referring to, but it's probably nothing more than a bad chain. You can replace the chain while the TC is still in the rig.
Click to expand...

Well, when I'm in 2wd and hit the gas, there's a bit of lag between the time the transmission has clearly got torque and the time my rear wheels actually start moving. A loose chain sounds about right.
When in 4x4 however, when I hit the gas, it KNOCKS something horrible. Feels like the front output shaft is spinning a quarter turn before engaging the front DS.

So, I climb under, in 4x4, in gear, stopped and chalked, and give both DS's a spin by hand. The rear has a little movement, but the front rotates a good 8-10 degress before hitting the gear. this probably means it's both my front output on the t-case as well as bad gears on the front diff. Any better idea's?

(p.s. my buddy just lost his jeep off a cliff and rolled 3 times, so the jeep is 50km back into the bush up a mountain. free axles and t-case if I can crawl up there to recover them :) )
 
blistovmhz said:
Well, when I'm in 2wd and hit the gas, there's a bit of lag between the time the transmission has clearly got torque and the time my rear wheels actually start moving. A loose chain sounds about right.
Click to expand...

The chain is only involved in 4wd - the chain connects the front output to the rear output. Anything you feel in 2wd is not chain related.

blistovmhz said:
When in 4x4 however, when I hit the gas, it KNOCKS something horrible.
Click to expand...
This could be the chain.
 
Makes sense. Sounds like it's just a combination of the chain and a bit of imagination. :)

How do I verify the chain is hooped and in need of replacement?
 
Whats the mileage on the jeep, and how often did you check the fluid level? My 231 on my last '94 had no fluid in it for about 3k, before I started noticing a noise in 2wd, that when I went to 4wd got horrendous. The chain was contacting the case, but not through it. Tore it down, replaced the innerds with bastard parts + the case, and most of the parts from a '98 TJ that was totalled after hitting a guardrail. Fluid inside it was clean, and good, we just took both apart on the bench, rebuilt 1 and the guy I got it from kept my old worn parts. It functioned flawlessly for almost 50k before I hit a tree. My current '94 has a 242, so I am going to see just how much better or worse it is than the 231, but I am sure that there really isn't much of a difference other than the Full Time option. Id just rebuild yours and be done with it. You'll be happier and the $$ spent won't be near as much as trying to find a later model one and doing the swap(cause the 242 might need rebuilding as well), + the SYE aren't swappable between the 231 and 242.

Jeff
 
ihscoutlover said:
Whats the mileage on the jeep, and how often did you check the fluid level? My 231 on my last '94 had no fluid in it for about 3k, before I started noticing a noise in 2wd, that when I went to 4wd got horrendous. The chain was contacting the case, but not through it. Tore it down, replaced the innerds with bastard parts + the case, and most of the parts from a '98 TJ that was totalled after hitting a guardrail. Fluid inside it was clean, and good, we just took both apart on the bench, rebuilt 1 and the guy I got it from kept my old worn parts. It functioned flawlessly for almost 50k before I hit a tree. My current '94 has a 242, so I am going to see just how much better or worse it is than the 231, but I am sure that there really isn't much of a difference other than the Full Time option. Id just rebuild yours and be done with it. You'll be happier and the $$ spent won't be near as much as trying to find a later model one and doing the swap(cause the 242 might need rebuilding as well), + the SYE aren't swappable between the 231 and 242.

Jeff
Click to expand...

This is the answer I was looking for :).
It's only got 230k on it. I figured I'm good for at least 400k as I've owned 4 other XJ's which all moved over 400k without any driveline issues. Perhaps I'm just lucky?
I haven't even checked the tranny/t-case oil yet, but I'll bet it's low :(.
what I really needed to know was the sye compat between the 231 and 242. That answered, I'll just rebuild my 231.

Jeff, what parts did you have to replace? Sounds like you had exactly the same symptoms as I've got.
 
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