NP231 T-case question

[anotherjeff]

I have a NP231 that I've installed a SYE kit in that's currently in my '00 I6 auto XJ. I was thinking about switching it into my 'new' 88 I6 5spd MJ which also has a NP231. Will this work or is there a difference between the auto and manual t-cases?

Thanks in advance.

 

[JeepFreak21]

I have a NP231 that I've installed a SYE kit in that's currently in my '00 I6 auto XJ. I was thinking about switching it into my 'new' 88 I6 5spd MJ which also has a NP231. Will this work or is there a difference between the auto and manual t-cases?

Thanks in advance.

You wanna swap the SYE kit or the whole t-case? What kind of SYE is it (Hack and tap or other)?
Billy

 

[cher96]

There are versions of the NP231 that take 21 and 23 spline input shafts. The 23 spline version is used behind the AX-15, AW4, and NV3550. The 21 spline is used behind the AX-5 and the BA-10/5. What tranny do you have in the '88?

Manual Transmissions that may or may not be in your '88
T4 or a T5 may have been used instead of an AX4 or an AX5 due to supply shortages.
AX5 - 5 speed manual - manufactured by Aisin - used with 2.8L V6 and 87+ with 2.5L I4
BA10/5 - 5 speed manual - manufactured by Peugot - used only up to 89
AX15 - 5 speed manual - manufactured by Aisin - used with 4.0L I6 engines

 

[anotherjeff]

There are versions of the NP231 that take 21 and 23 spline input shafts. The 23 spline version is used behind the AX-15, AW4, and NV3550. The 21 spline is used behind the AX-5 and the BA-10/5. What tranny do you have in the '88?

Sorry, it's the AX15.

You wanna swap the SYE kit or the whole t-case? What kind of SYE is it (Hack and tap or other)?
Billy

I was thinking of swapping the whole t-case. It's not a Hack and Tap, it's a Tera HD SYE Kit from PORC.

http://www.performanceoffroadcenter.com/oscommerce/product_info.php?products_id=3513

 

[Clean Racing]

I have a NP231 that I've installed a SYE kit in that's currently in my '00 I6 auto XJ. I was thinking about switching it into my 'new' 88 I6 5spd MJ which also has a NP231. Will this work or is there a difference between the auto and manual t-cases?

Thanks in advance.

No it wont work and here is why... The 88 has a different pitch cut in the planetary gears than the 00 does, and this also is translated over to the input shaft. So taking the cases out and swapping over inputs will not work either.. I would look for a 97+ 4 cyl wrangler to grab the input out of to make it work in your 00 case to put in the 88 MJ. I hope this helps..

 

[XJ_ranger]

No it wont work and here is why... The 88 has a different pitch cut in the planetary gears than the 00 does, and this also is translated over to the input shaft. So taking the cases out and swapping over inputs will not work either.. I would look for a 97+ 4 cyl wrangler to grab the input out of to make it work in your 00 case to put in the 88 MJ. I hope this helps..

While this is true - the output shafts are interchangeable.

you can re-use the SYE part of the case from the '00 and just follow the same directions for the MJ and install the output into the MJ case. :thumbup:

 

[anotherjeff]

DELETE

 

[4xBob]

The late model t-case will have the electronic speedometer sensor, while the 1988 jeep will use a mechanical sender. You will need to keep the mechanical system if you want the speedometer to work.