NEWS PARTS JEEP & 4x4 ATV & UTV

Differeances in 231's?

693 Views 10 Replies 6 Participants Last post by WILL, Nov 20, 2003

445

Discussion Starter · Nov 18, 2003

Differeances in 231\'s?

I need a t-case for my tj and need to make sure i get the right one, i have a '97 tj with an auto. What years were the differances in 231's? I'll probably be getting one out of an xj. From what i know i have a 23 spline 231 and they came behind high out put 231's, is that correct? So i pretyt much need to get one of of a '91 or newer jeep? As far as i know in '97 the outputs changed so if i wanted to use my current slip yoke i would need a '91 or newer case? That doesn't really bother me since i'm going to put a sye on it so it just matters to which sye i order. Am i on the right track here or totally missing something?

BarrelRoll

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JeepnGreg

· #2 · Nov 19, 2003

Re: Differeances in 231\'s?

you have a 23 spline tranny since you had the 6 cylinder. from my understanding the 23 spline t-cases were behind the ax-15, nv3550,

the 21 spline cases were used behind the ax-5 and BA-10.

im not sure if there was a difference between the t-cases on automatics.

from what i understand the TJs had a different output in the back so that you can take off the drive shaft and not lose fluid......so im not sure if you could use yur SYE on a 91-95 case.....

i think your best bet is to get a 97+ t-case from a 6 cylinder XJ or TJ (maybe zjs too) and count splines.

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WILL

· #3 · Nov 19, 2003

Re: Differeances in 231\'s?

In reply to:

from what i understand the TJs had a different output in the back so that you can take off the drive shaft and not lose fluid.....

[/ QUOTE ]

No, you must be thinking of the transfer case used in the Rubicons. The 231 used in TJ's is the same as the YJ's.

JeepnGreg

· #4 · Nov 19, 2003

Re: Differeances in 231\'s?

im just going by what i read on the ORC jeep section for 231's a while back, checked again today and thats what it says...

also, if you do happen across a 21 spline apparently theres a conversion kit available for 23 spline

445

Discussion Starter · #5 · Nov 19, 2003

Re: Differeances in 231\'s?

I'm putting a sye on the t-case so if i use an eariler one i will just order an sye for an eariler case. What i'm asking is what is the earliest year i can pull one from and get the right spline count.

BarrelRoll

bandhmo2

· #6 · Nov 19, 2003

Re: Differeances in 231\'s?

My under standing is that there are three differences in NP231's.

1. Bolt pattern of input side. Jeep and Dodge used the same 6 bolt pattern. Ford and chevy veryed but I think they used the six bolt pattern from time to time.

2. Spline count. Jeep used both 21 and 23 spline. 23 spline is standard in later years but 21 stayed around a along time especally behind automatic tranys. I beleive Dodge use only 23 splines on NP231's

3. Input length. Jeep used both long and short inputs. Basicly some years the trany output shaft stuck out further then others. I am not sure of the year bracks on this. Not sure which Dodge used.

My I sugest going to Novak's and Advanced Adaptors web sites, they both have some very good information on Transefer case inputs for use in trany swaps that would likely answer most of your questions.

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027

· #7 · Nov 19, 2003

Re: Differeances in 231\'s?

In reply to:

What i'm asking is what is the earliest year i can pull one from and get the right spline count.

[/ QUOTE ]

Ok you can use any 231 with a 23 spline count from a 88 YJ up to a 2000 TJ or any 231 with 23 spline count from a 90 XJ up to 2000 XJ. Keep in mind the older 88-93 231's had a little better bearing set up than the newer ones because of the bushings subsituted for the bearings. but any JEEP 231 has the same bolt up and input / output shaft length for stick or auto. You may run across some that have the SYE already installed but most had the slip tail shaft. Now the operating levers may vary on the different years and are diff on the XJ but all are interchangable to the various year JEEP 231. Hope this answered your question

G

· #8 · Nov 19, 2003

Re: Differeances in 231\'s?

here hope this helps, the Tj and YJ tailshafts are differnt so dont get that cofused!
231 differnces

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WILL

· #9 · Nov 20, 2003

Re: Differeances in 231\'s?

I'd like an explaination of how the TJ is different.

959

· #10 · Nov 20, 2003

Re: Differeances in 231\'s?

also the NP231 t case have different input shafts between the auto and the 5 spd. not only do you have 21 or 23 spline, you also got short or long. check out the advanced adapter web site. they have a PDF with a nice picture that shows the diferences.

wil,
the tail shaft housing is different. between the TJ and YJ. the TJ tail shaft housing is shorter it looks similar to the tail shaft housing that came with the AA HD SYE kits.
the slip yoke rides in a boot.

if you do a rubicon express hack and tap SYE the kits are different( YJ to TJ) and the TJ kit is $100 buck cheaper cuase it only includes the bolt-on flange for the drive shaft. becasue it has a shorter housing.

greg

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WILL

· #11 · Nov 20, 2003

Re: Differeances in 231\'s?

Thanks.

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