XJ tranny and transfer

[jharrison13]

I was wandering if going to a jeep dealer and giving them the vin# if they would be able to look up and see what tranny and transfer case are in a jeep?

[BrianXJ]

You can request a build sheet for your XJ here is how to do it

:link: (http://www.xjtalk.com/showthread.php?t=493)

[bigjim350]

If you just post up the year, and what kind of jeep, auto or 5sp and I can tell you what trans is in it. The t-case is pretty easy to figure out also

[Metlic53]

You can request a build sheet for your XJ here is how to do it

:link:

linky no workky?

[XJ4IV]

most likely a AW4 and a NP242... SOOOOO freakin common
if its a 6 cyl with a manual its got an AX15 and a NP231... those are basically the ONLY setups in a XJ... you can aldo get the AW4 and the NP231 but cant do the AX15 with the NP242 for some reason

NP231 is
2HI
4HI
N
4LO

NP242 is
2HI
4HI
N
full time
4LO

[BrianXJ]

linky no workky?

Fixed

[jharrison13]

just submitted the info thanks for the help.

[jharrison13]

i climbed under the jeep a few minutes ago and on the id plate it has a 231 on the model i assume tha means i have a NP231 right?

[bigjim350]

i climbed under the jeep a few minutes ago and on the id plate it has a 231 on the model i assume tha means i have a NP231 right?

Correct

[jharrison13]

now i have to get my 96 out of the mud and get under it and see what it is, if it is the 242 it will bolt up to mine right? it is just a little different as in the full or part time right? which one is better? the reason i ask is because it and the transmission are both new . that is why i havent got rid of them yet. my father in law had someone put them in new and drove it about 100 miles and through a rod and parked it so talked him into giving it to me, so it has set in the barn for a few years now just in case and now i have an xj i can use it for parts.

[bigjim350]

Yeah the NP242 should bolt up, you may need to swap over shifter linkages too. You don't need to climb under the xj to see if its a 242. Just look at the shift indacator beside the T-case shifter. If it has a fulltime 4wd option, it is a 242

[jharrison13]

this may be a little to technical, in the 242 and the 231 are the gears or the bearings the same? because if there are some parts that are the same i woudl just keep it for the parts and keep mine in there, if they are different,

[LizardRunner]

The Jeep NP 231 transfer case was introduced in the 1988 model year. Jeep's YJ Wrangler and the XJ / MJ Cherokees with the Command Trac option were the first models to feature it. The 231 was initially tagged as the 231AMC, and as ownership of AMC was taken over by Chrysler, it was later designated as the 231J. This transfer case was later to be called the NVG (New Venture Gear) 231J. Despite the different nomenclature, they are essentially the same transfer case, with the bulk of their parts interchanging.
Chain driven transfer cases were first used in the 1970's with partial success - Jeep's Borg Warner QuadraTrac being a notable instance. They increased in reliability and strength in the early to mid-eighties and essentially hit their stride in the late-eighties. The 231 has continued in the trend of chain-driven cases and is one of the most successful and popular of them all.
Features
The 231 has a driver's side front output and centerline rear output. The NP231 features two ranges; a low range gear that is a respectable 2.72-to-1 (the lowest of all the Jeep transfer cases with the exception of the NP241OR) and a direct-drive in high range. It features three modes; two-wheel-drive, four-wheel-drive and neutral - for a factory combination of 2H, 4H, N, 4L. Aftermarket modifications allow for the addition of a 2 Low position.
Early 231s from 1988 through 1991 featured a conventional mechanical (cable) drive speedometer output. In 1992, Jeep introduced a three-wire, digital square wave Vehicle Speed Sensor (VSS), in the vein of modern automotive systems.

The design of the 231 is very good. They were engineered for durability and simplicity of build - both an advantage to the OEM assemblers as well as individuals servicing them. The NP231 transfer case has turned out to surprise us in its strength, gearing, upgradeability and servicability. Most of our customers choose to retain their Jeep 231 with their conversions. It is very common for them to offer good service behind some of the strongest engines and transmissions.
The standard 231 weighs about 70 lbs. HD 231's can weigh up to 80 lbs.
Identification
This transfer case is identified by its red and silver tag on the rear of the case. They are also easily identified by appearance. They feature a six-bolt front face.
There are Chevy & Dodge versions of the 231. The GM versions use a five-bolt front face that is incompatible with the Jeep and Dodge six-bolt styles. The Chevy versions also use long factory adapters and have no support for improvements - particularly in shifter upgrades and tailhousing upgrades like those available for the Jeep versions.

Heavier-duty HD and DHD units are available in ZJ Jeeps and Dodge trucks, respectively. The standard duty OEM 231 transfer cases are capable of transferring from 1600 to 1900 ft. lbs of torque (as claimed by NVG - actual experience puts this number quite a bit higher).
Wide chains, larger planetaries and stronger mainshaft/tailhousing assemblies (see Tailhousings, below) are also available if even more strength is desired. With such upgrades, a transfer case capable of handling 2900+ ft. lbs. of torque is attainable. This is a result of good engineering and refinement.

The Jeep NP242 transfer case was introduced in the 1987 model year as a replacement for the NP228. The 242 premiered in the XJ Cherokee / Wagoneer and MJ Commache as the SelecTrac option. It was used in the 1991-1998 ZJ Grand Cherokee. The 242 persisted throughout the full run of XJ Cherokees and continued on in the 2002 KJ Liberty.
The 242 was originally tagged as the 242AMC, and as ownership of AMC was taken over by Chrysler, it was later designated as the 242J. This transfer case was later called the NVG (New Venture Gear) 242. Despite the different nomenclature, very few mechanical changes were required or made throughout their production span.
Earlier attempts at torque-biasing transfer cases were spotty in their success, beginning with the QuadraTrac in the 1970's and continuing with the NP219 and NP228. The 242 has continued in the trend of chain-driven cases and has technically and commercially been more successful than its predecessors.
Features
The 242 has a driver's side front output and centerline rear output. The NP242 features two ranges; a low range gear that is a respectable 2.72-to-1 low and a direct-drive in high range. It features three drive modes; 2wd, full-time 4wd and part-time 4wd, yielding:
two-wheel-drive, high (direct-drive)
four-wheel-drive, high (48/52 differential torque-biased-drive)
four-wheel-drive, high (locked, part-time)
neutral
four-wheel-drive, low (locked, reduction-drive)

Though Full-Time is the nomenclature used, this is a position that is used sparingly, as component wear throughout the geartrain and tires is a result, in addition to decreased fuel-efficiency.
Early 242s from 1988 through 1991 featured a conventional mechanical (cable) drive speedometer output. In 1992, Jeep introduced a three-wire, digital square wave Vehicle Speed Sensor (VSS), in the vein of modern automotive systems.
The design of the 242 is fairly good. They were engineered for durability and simplicity of build - both an advantage to the OEM assemblers as well as individuals servicing them. The NP242 transfer case has turned out to be stronger than expected. Most of our customers choose to retain their Jeep 242 with their conversions. It is very common for them to offer good service behind some of the strongest engines and transmissions.
The 242 weighs about 85 lbs.

This transfer case is identified by its red and silver tag on the rear of the case. They are also easily identified by appearance. They feature a six-bolt front face and a longitudinally ribbed barrel case.
There is a GM version of the 242 as used in the H1 Hummer (1990- ) and the later H2. It features a different front face bolt pattern that is incompatible with the Jeep six-bolt styles. This GM version is rated at a stronger duty by virtue of its stronger output shaft. It may feature a 1" wide or a 1.25" wide chain.
Interestingly, New Venture documents show the 242 as being rated at 1486 ft. lbs. of torque. This is probably determined based on Full-Time position usage. Experience would say that this is a very conservative number for all other positions.

All that information was taken from the Novak Conversion knowledge pages.

Hope that comparison info helps you out. I don't think any parts are actually "interchangable" The 242 is a longer case and usually has wider gears and chain than the 231.

[4.3LXJ]

One more thing I would add. There is more after market support for the 231. If you are looking at lifting the vehicle significantly, then a slip yoke eliminator is in your future. Only one is available for the 242, the hack n tap which requires some drilling and tapping. The 231 has several very strong options for this.

[LizardRunner]

yep, I forgot to mention that there is lots more support/options with the 231.

[jharrison13]

that helps alot, that has pretty much answered all my questions. thanks for all your help and info.

[jharrison13]

i used that link and finally got a reply back and they said they are to busy to help me. and that i should go to my local dealership for further assistance.

[4.3LXJ]

So refresh my memory, what is it again you want to know?

[jharrison13]

i was looking for the specs on my 2 jeeps for parts that wil work on each other, i have 1998 4dr se with 231 and automatic, and a 1996 2dr sport with automatic and i think it is a 231 also,