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Does anyone know if a 1993 231 will worl on a 1997 AW4?

J

JEEPTUBE

NAXJA Forum User
Location
citrus heights
This has been a pain in the ass for me to get exploded views of the 93 np231 and the 97 np231. s well as the 93 AW4 and the 97 AW4.

Let me get to it now.
Lets say u unbolt the 242 off the 97 AW4. And u look at the output splined shaft on the 97 AW4.
Then u do the same on the 93 AW4 with the 231 and look at the output splined shaft on the 93 AW4. (note we are not talking about the t-case output right now).

So are both 93 and 97 transmissions mechanicaly the same? Transmission splined output shafts?
length and diameter?

:gonnablow
 
Thanks for all the info guys. 87manche, i will be calling novak immediatly. I had a 4 wheel drive shop change the input gear about a year ago. And since then been having a strange noise coming from the t-case almost like a pulsating humm. I called that shop back and they said that it must be something else. I checked and its not somrthing else. What will this damage if i have the wrong input gear?
There are five diff versions of the input gear for the 231.
I def have a 23 spline because if it was a 21 it wouldnt fit tight right?
long
short
medium
early cutt
late cutt
short bearing
wide bearing
 
Last edited:
The 42RE has a pilot hole in the back of the gear, but even a tcase from one of them will bolt up. (I test fit a '93 ZJ with AW4 tcase onto a '96 ZJ 42RE and it buttoned right up)
 
carnuck said:
The 42RE has a pilot hole in the back of the gear, but even a tcase from one of them will bolt up. (I test fit a '93 ZJ with AW4 tcase onto a '96 ZJ 42RE and it buttoned right up)
Click to expand...

U test fit an 93 ZJ with AW4 t-case?
Do u mean u have a 97 ZJ with an AW4 and used a 96 42 RE and bolted it right up?
We are talking about the differences in input gears and what years and applications the 231 had them.

And in length and diameter and spline count of the output shaft on the AW4 in the XJ from 1991 to 1997.
 
The '93 ZJ I parted was AW4 from the factory (only early '93 were) and I took the NV249 from it and bolted it to the 42RE core I have sitting in my shop.
I also test fit a Jeep NP208J to both trans. A 7/8" D300 clocking ring fits just right to space them apart. (The clocking ring I have was stolen from my truck then returned a couple weeks ago)
As of 08/90 the AW4 became 23 spline till the end of production.
 
carnuck said:
As of 08/90 the AW4 became 23 spline till the end of production.
Click to expand...
correct, I don't think that any physical changes were made after the change to 23 spline.
The gear cuts are internal to the t-case, and that would be important if you had to change input gears. You shouldn't have to change input gers, so just bolt it up.
 
I got 5 different part numbers of input gears for the 231 in 1993. That was from the stealership. Remember i am installing a 1993 231 t-case on my 1997 AW4.
Yes they are 23 spline BUT for the 1993 t-case it came in 5 different types.
Look at the novak post u sent me.
The 1997 242 input gear part number is-4798126
Can i install that input gear into my 1993 231.
Since i cant match any of the input part numbers in the 1993 231 to the 242 input gear part number.
What do i do?
Can i take the input gear from the 242 that i have now and install it into the 231?
Or will it not work?
 
And what in gods name is the whole purpose of having 6 different input gears?
They are all for a 23 spline AW4 transmission.
Are there different output shaft legths on the AW4 intself?
 
JEEPTUBE said:
And what in gods name is the whole purpose of having 6 different input gears?
They are all for a 23 spline AW4 transmission.
Are there different output shaft legths on the AW4 intself?
Click to expand...

One reason being that in 95 the input gear tooth design changed.
The input gear teeth mess with the small planeteries and then with the annular ring for the low range. All these teeth have to be of the same design or you risk premature wear, noise etc.
To succesfully replace the entire TC you need one with an input shaft like the one you removed as far as length and splines are concerned.
To replace an input gear in the TC with another, you need the same length, splines and one additional item, tooth design.
 
JEEPTUBE said:
I had a 4 wheel drive shop change the input gear about a year ago.
Click to expand...

If you had the input gear only swapped from one TC to another, years 93 and 97, I have the sneaky suspicion that you got screwed big time.
They look identical but they are not. A very close look will reveal a different design of the teeth.
If my suspicion is correct, you have to replace the TC. The input gear screwed
up itself and the planetaries and the planetaries screwed up the annular gear which is not replaceable. You could salvage the front case and many parts, but, you would most likely be better off replacing the whole TC.
On second thought, if you had gears grinding on each other and little fillings floating all over,
I think you get the point.
 
Last edited:
Yes i totaly agree with u falcon. When the guy took it apart, i dont think he matched the tooth pattern as far as late or early cutt on the input shaft to match everything inside the t-case. As far as the shaft itsself. It is all good on the length of it. If its too short it will not insert all the way to the tranny output shaft. If its too long it will damage the tranny being crammed into it.
Another thing is. Bearing that goes on the inputshaft could be fubared. Likewise making the bad noise. He did put on a used one.
 
JEEPTUBE said:
And what in gods name is the whole purpose of having 6 different input gears?
They are all for a 23 spline AW4 transmission.
Are there different output shaft legths on the AW4 intself?
Click to expand...

I don't believe the AW4 output shaft ever changed. I have an 1989 NP231 (originally AX15, so 23-spline) mated to a 1999 AW4. There are some differences in the tranny sensors pre/post mid 1996 in the AW4 and you'll need to use the later TCU.
 
lawsoncl said:
I don't believe the AW4 output shaft ever changed. I have an 1989 NP231 (originally AX15, so 23-spline) mated to a 1999 AW4. There are some differences in the tranny sensors pre/post mid 1996 in the AW4 and you'll need to use the later TCU.
Click to expand...

I used to have a '87 with 4.0, AW4, 242. When the time came to retire it, I considered swapping the 242 with the 231 in my 96. That's when I found out that the early AW4s had 21 splines and the post 90 have 23 splines.
This spline count has to do with AW4 only. AX15 are not the same. They are not automatics and they are not made by AW. Apples and oranges.
 
As far as the input gear length and spline count, it is perfect.
But since i cant see whats inside. Im going to have to pull the t-case and disect it. I will check the bearing and tooth pattern.
If the tooth pattern was incorrect installing the inputshaft, wouldnt the gears just grind on eachother until it started slipping?
What noise would that make?
It would be terrible right?
If the bearing on the input shaft took a crap, what would that sound like?

 
JEEPTUBE said:
87manche
would these noises occur constantly in 2 wheel drive?
Or would i have to engage it in 4 wheel drive?
I wonder if it could be worse engaged.
Click to expand...

I imagine the worst gear noise would be in 4Low because it uses all of the gear teeth.
Just an opinion, no facts.
 
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