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NP231 manual and auto transmission difference

Discussion in 'Wrangler YJ (1986-1995)' started by Earl94yj, Jun 16, 2019.

  1. Jun 16, 2019 at 5:27 PM
    #1
    Earl94yj

    #1
    Earl94yj [OP] EarlYJ

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    Looking for replacement parts for a YJ wreck and had a question. What is different in NP231 transfer cases between 4 and 6 cyls and auto and manual transmission? Also want to broaden my options into Cherokees or maybe even Comanches if I run accross 1 in salvage.
    Thanks
    Earl
     
    Earl94yj, Jun 16, 2019
    #1
  2. Jun 18, 2019 at 6:59 AM
    #2
    Prerunner1982

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    Prerunner1982 Well-Known Member

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    Between 4 cylinders and 6 cylinders the input spline count is different, 21 vs 23.
    After 92 (At least for the XJ Cherokee) the spline count for the 6 cylinder regardless of transmission was 23, prior to about 1990 the AW4 was 21 spline.
    There are also short, medium, and long input shaft versions depending on what transmission they came behind.
    https://www.novak-adapt.com/knowledge/np-nvg-input-gears/

    Also the Cherokee/Comanche tcase is clocked down a bit more than the Wrangler which would help the driveshaft angle a little but you may run into a problem with it hitting the skid plate.
     
    Prerunner1982, Jun 18, 2019
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    aggrex likes this.
  3. Jun 18, 2019 at 2:41 PM
    #3
    Earl94yj

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    Earl94yj [OP] EarlYJ

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    So
    With this I read that the tcase behind an AX 15, which is in my 94 YJ with the 4.0 and a tcase behind an automatic from a 95 Cherokee with the 4.0 should work.
    Correct?
    Or am I reading it wrong?
    I have a dropped skid plate for my lift so shouldn't be an issue
    Earl
     
    Earl94yj, Jun 18, 2019
    #3
  4. Jun 19, 2019 at 10:36 AM
    #4
    Prerunner1982

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    Prerunner1982 Well-Known Member

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    That is my understanding as well based on the info I have found.
     
    Prerunner1982, Jun 19, 2019
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