Okay, I know that the NP231 is not hard core, but here it goes.

I blew up (http://www.texasbbqrub.com/blake/DSC00959.JPG) my NP231 a few days ago when my driveshaft tore off, causing a hole in my weak ass aluminum transfer case. I am taking it to a welder tommorow to see if a patch can be put on it, but more than likely it is going to be replaced.

I've found lots of NP231s in the for sale section, but my problem is I have the TF904 transmission, which has different output shafts. Mine has 23 spline but it sits flush with the transmission. The AX15 has 23 spline but protrudest 1/2" beyond the tranny.

My question is, if I get another NP231 that has a different output shaft, couldn't I just take the one out of my current NP231 and place in the new one I get? Also, would it matter at all what kind of shaft it had since I could just put the one from mine in it? My case model is 52097893

Thanks in advance,

Blake "my jeep sucks" Cannon

Im guessing you have a 4-banger auto YJ.

All the 231 cases are the same from 87-00 YJ, TJ, XJ, ZJ. Just swap the input gear in the new font half of the case with your current input.

Originally posted by Jeepin_NC
Im guessing you have a 4-banger auto YJ.

All the 231 cases are the same from 87-00 YJ, TJ, XJ, ZJ. Just swap the input gear in the new font half of the case with your current input.

That's what I figured. I was just checking before I plop down money, tear it apart, and then have it end up not working.

:beer:

So, if the NP231 sucks, why put another one in its place, when you've already blown up one? Why not do something stronger? It might be more $$, but you shouldn't break it.
Scott

Originally posted by Ketchup Dog
So, if the NP231 sucks, why put another one in its place, when you've already blown up one? Why not do something stronger? It might be more $$, but you shouldn't break it.
Scott

Oh, the question finally arises

Because I'm in debt. Cant' afford Atlas, can't afford a D300 or a flip kit, or to swap axles to use a normal D300. I can get a NP231 for cheap. Nor do I have the time. I can't really mess with it that much until I get a truck.

Not all of us fart quarters.

Ok, that makes sense then. I understand the whole debt thing. I was there once, heck I still am in one way or another. You can just swap out your input shaft on the front half of the case, and stick it in the new case. Its not all that hard.
Scott
PS.. I like my 231. :D

Since it is already apart... You should put the larger chain in it. That with the better upgrade SYE kit, and the transfer case isnt all that bad, other than the :rainbow: aluminum case. I blew one up when a front driveshaft overcompressed from a rock deciding it did not want to give at 30 mph. Silly rocks.

BTW if any of your internals are toast. PM me I'll send ya some really cheap. I have the guts for a case sitting in my garage.

Ben

Hahahah. It's not apart yet. I've got to get the case first. Right now I have the most ghetto fix ever. Screen wire and JB weld over the hole to get me to school to take my tests this week :D

Originally posted by jeepboyben
other than the :rainbow: aluminum case

If aluminum cases are :rainbow:, then is the Atlas :rainbow: too:question::flipoff2:

Fawk, i just looked at a tear down of the NP231 for the Tera Low kit. It seems pretty simple, but it doesn't show them getting ot the input gear. Is it going to be THAT much more work? I'm seriously debating whether to get the Tera Low kit since it's all ready to go. Damn i'm about to have a heart attack, I have to get my Daily drive running

Originally posted by Michelle

If aluminum cases are :rainbow:, then is the Atlas :rainbow: too:question::flipoff2:

They are machined out of one massive piece of cast aluminum instead of split in two like an np231....I think that is a benefit.

I also don't think there is anyone here arguing an aluminium atlas is weak :flipoff2:

Originally posted by Jeepin_NC
Im guessing you have a 4-banger auto YJ.

All the 231 cases are the same from 87-00 YJ, TJ, XJ, ZJ. Just swap the input gear in the new font half of the case with your current input.


they're not all the same, the pitch on the planetaries changed, as well as the output shaft later on.

i'm not sure, but I think the change in the gear pitch may effect the input gear working properly in a swap situation.

double check just to make sure.

Originally posted by 1337j33px0r

they're not all the same, the pitch on the planetaries changed, as well as the output shaft later on.

i'm not sure, but I think the change in the gear pitch may effect the input gear working properly in a swap situation.



True, the pitch will change, then the case number changes too.

To be more specific:
The case will be the same for input gears (23 SPLINE) with case number #'S 53008210, 52097893 OR 52098048.

Originally posted by Michelle

If aluminum cases are :rainbow:, then is the Atlas :rainbow: too:question::flipoff2:

Well I would prefer a stronger case on the Atlas since a friend of mine grenaded his Atlas aluminum case the same way I grenaded my 231. By running the front driveshaft through it. AA is good enough to stick his internals in a new case for $800 :eek: So yeah I think aluminum cases are :rainbow:

:flipoff2:

Ben

Originally posted by jeepboyben


Well I would prefer a stronger case on the Atlas since a friend of mine grenaded his Atlas aluminum case the same way I grenaded my 231. By running the front driveshaft through it. AA is good enough to stick his internals in a new case for $800 :eek: So yeah I think aluminum cases are :rainbow:
:flipoff2:
Ben

Time for a shaft craddle.

Or a front driveshaft with enough slip. He got lazy.

Originally posted by jeepboyben


...a friend of mine grenaded his Atlas aluminum case the same way I grenaded my 231. By running the front driveshaft through it.

Sounds like it's time for a properly engineered front suspension and a driveshaft with the proper amount of travel, just because it fits doesn't mean it works.

Anyway, yeah, the pitch on the planetary assembly changed around '95, all of the 4cyl cases had the new assembly, which means the input gear for that application costs more. If both your case and the one you are swapping are both before or after '95 you should be safe. You could swap the whole planetary assembly if you've got two different ones, they should be interchangeable.

Ive been told before not to weld on the case, its better to find one that aint fawked up. 231's are cheap just get a newer cawse.