NP242 T-case replacement options?

I have a NP242 t-case that is in need of rebuilding or replaceing. If I want to replace with another used one, will the NP242 from other Jeep vehicles bolt up where mine comes out of?
Basically it is a question of whether a newer t-case will work in the older Cherokee without major headaches.

I have a 1990 XJ with automatice trans.
Thanks

The 242s are harder to find, but you could use a 241 instead also. Rebuilding is an option, what is wrong with it? It is all about the cost.

You also mentioned using a later one, so you will need a "fix" for the vaccum disconnect Dana 30 front axle too. The late model 231 is all mechanical linkage and non-disconnect front axle.

Also, latter transfer cases may have different spline counts on the input shaft, depending on the respective transmissions used.

AlohaBra said:

The 242s are harder to find, but you could use a 241 instead also. Rebuilding is an option, what is wrong with it? It is all about the cost.

You also mentioned using a later one, so you will need a "fix" for the vaccum disconnect Dana 30 front axle too. The late model 231 is all mechanical linkage and non-disconnect front axle.

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The 242 equipped XJ's from the factory did not use a vacuum disconnect front axle.

A 90 242 should be 23 spline, i'd pull it out, count the splines and then find your replacement. I bought a replacement (242) for my wife's 231 for $100...some guys dont want the 242.

Okay,now this brings up a new question. I found a 242 from a 90 that the guy says has 21 splines. Is spline count different from manual to auto transmission?

the 242 was never available with the Manual Trans if i remember correctly.

Per Woody's recent article, I too am looking to put in a 242 in replace of my 231 in my 98' and didn't know 23 spline started in 90', I thought 91' with the high output:

"The following 4WD transfer cases were utilized on the various XJ/MJ models throughout the production run.

New Process NP207 Command Trac: 2-speed, chain-drive, part-time 4WD. 2:72:1 low-range. 84-86 2.5l 4cyl and 2.8l V6 models with manual or automatic transmissions. 21-spline input. These used a vacuum switch to activate the dash indicator lamp and engage the front axle disconnect. The shift indicator pattern is 2WD > 4WD high range part-time > Neutral > 4WD low range part-time.

New Process NP229 Select Trac: 2-speed, chain-drive, part or full-time 4WD. 2:72:1 low-range. 84-86 2.8l V6 models with automatic transmission only. 21-spline input. The shift indicator pattern is 2WD > 4WD high range part-time > 4WD high range full-time > Neutral > 4WD low range part-time.

New Process NP231 Command Trac: 2-speed, chain drive, part-time 4WD. 2.72:1 low-range. 87-01 2.5l 4cyl and 4.0l I-6 models with manual or automatic transmission. 87-89 21-spline input, 90-01 23-spline input. The older models used a vacuum switch to activate the dash indicator lamp and engage the front axle disconnect. Newer (non-disconnect axle) versions used an electrical switch to activate the dash lamp. The shift indicator pattern is 2WD > 4WD high range part-time > Neutral > 4WD low range part-time.

New Process NP242 Select Trac: 2-speed, chain-driven, part or full-time 4WD. 2.72:1 low-range. 87-01 models with 4.0l I-6/AW4 automatic transmission only. 87-89 21-spline input, 90-01 23-spline input. The shift indicator pattern is 2WD > 4 high range part-time > 4 high range full-time > Neutral > 4 low range part-time.

Common to all New Process/New Venture transfer cases is an round ID tag on the rear case half. This will indicate the model and serial number. OEM Jeep transfer cases are indicated by the "J" designator (ex: NP231 J) and other OEMs had their own designators (C= Chevy, D= Dodge, AMG= AM General etc...) there is some crossover between parts within the various OEMs, but I won't get into that here.

Throughout the production run, input spline counts and other internal specs changed, and must be compatible with the transmission it's mated to. The later model cases (1996.5 and newer) changed styles of rear slip yoke to an internally sealed version. When replacing parts, performing upgrades, or replacing the case entirely, one must take care to insure the new parts/assemblies are compatible with what is in presently" per Woody, thanks bud!

CommandoXJ96 said:

the 242 was never available with the Manual Trans if i remember correctly.

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Yeah, I think that's true, I've seen hundreds if not a thousand XJs through the years and never saw a manual with the 242.

Also the V8 ZJs only had NP249 Quadratrac from the factory. There all scared we are going to overload the rear axle and break it driving through the mall parking lot!!! :laugh3:

Big Red said:

Per Woody's recent article, I too am looking to put in a 242 in replace of my 231 in my 98' and didn't know 23 spline started in 90', I thought 91' with the high output:

"The following 4WD transfer cases were utilized on the various XJ/MJ models throughout the production run.................................................................

New Process NP242 Select Trac: 2-speed, chain-driven, part or full-time 4WD. 2.72:1 low-range. 87-01 models with 4.0l I-6/AW4 automatic transmission only. 87-89 21-spline input, 90-01 23-spline input. The shift indicator pattern is 2WD > 4 high range part-time > 4 high range full-time > Neutral > 4 low range part-time................

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Apparently I am completely inept in using the search fuction even though I have read the http://www.naxja.org/forum/showthread.php?t=80053 "Guide to searching!!!!" thread too many times to remember.

Here are the "Cliff Notes" to my problem.

1. I am a Jeep newby.
2. I bought a '92 Limited that has the 4.0, AT and has the NP242 for weekend play. No intentention to trailer it. Secondary DD.
3. I developed driveline vibration issues due to lift. (parts are enroute to try to correct the issue)
4. Rear DS U-joint went and took the pinion yoke with it. Replaced the U-joints and yoke only to discover......



my tc cracked and obviously as a result of the DS violently flying around (or so I hope)

Should I assume that anything post '90 will the same spline count as my '92?

1990 is not the breakover year for 23 spline AW4s, it's 1995. Starting in 1996 the AW4 has 23 splines.

I have a 242 behind a AX15... I put it there myself... :laugh:

So to recap, any 242 from 1987 to 1995 will interchange. 1996 and up are different.

Later,
Joe

I disagree Joe...respectfully. 90 is closer to the changeover than 96.

I have several 94's and all are 23 spline.

Hmm, interesting... I have had a 1991 242 and it had a 21 spline (no telling if it was a leftover though). I was pretty sure that it changed sometime in the mid 1990s so I called my friend at a 'yard and had him run the compatibility list. The transmission interchange breaks are 1987-1990/1991-1996/1997-2001 so it looks like I'm wrong and the break is 1991. Of course, there's no telling what changed, just that the computer says they're different somehow.

Later,
Joe

From my data, 1990 is 21 spline and 1991 up is 23 spline. When you pull yours, it would be great if you could count the splines and post the result. I have a 1990 with 231 that I would like to change to a 242 like my wife's 2001.

I think there was some cross over as old parts were used up, but the main 21 to 23 spline cross over was with the HO 4.0 in 91. You can use an older t-case but you will have to change the input gear. If it is in good shape you could use the one from your old t-case, or buy one from the dealer. In 97 DC changed the output shaft configuration. For a 90 XJ I would look to any 90 or older XJ's with the 242 for a donor. 91-96 need to stay within that timeframe as do the 97 on if you aren't into swapping case internals.

I have swapped a couple of input gears and it is a fairly straight forward R&R. I may have the old 21 spline input somewhere in storage.

Bones :skull1:

Double Whammy '02

In one moment : Output shaft broke, rear t-case bearing housing broke, rear pinion yoke broke, rear drive shaft bent, rear axle housing bent, damaged front R&P, all because of a broken axle locating pin on the rear left leaf spring. At least it was all caught on camera

i'd like to see that carnage-filled footage

Whew, I would love to see that footage as well:shiver:

I spent 6 hours on the road yesterday to pick up a 242 out of a '91 XJ to use the rear carrier and extention housing. I cleaned up the donor's parts and was pulling mine off when I discovered the rear case was also damaged. I guess I get to learn more stuff now. If, any more carnage is discovered I think I will cut my loses and run.

bcsavage said:

i'd like to see that carnage-filled footage

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F9K9 said:

Whew, I would love to see that footage as well:shiver:.

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Get a hold of YellaHeep and see if he still has some of the '02 Fall Fest videos from Moab available. He and his lovely better half did an excellent job of videotaping the event, of which my was given its own chapter :anon:

Bones :skull1:

2 Days later...