NP231 input shaft swap 23 to 21 spline

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thanasi85

NAXJA Forum User

Location

Sacramento, CA

• Mar 20, 2013

• #1

So I have a 1988 jeep XJ 4.0l with automatic transmission and wanted to know if I could take the t-case off and remove the input shaft from it which is 21 spline and put it into another np231 t-case that I just bought that is a 23 spline. The reason I want to do this is because the 23 spline t-case I just got has a nice sye already installed and was recently overhauled with new bearing and seals

 

1990JEEPXJ

NAXJA Forum User

NAXJA Member

Location

San Diego

• Mar 22, 2013

• #2

Depends on the year of the new t-case. If its from pre-94 I believe then you are good. Has to do with the angle of the helical cut gears on the planetaries.

 

T

thanasi85

NAXJA Forum User

Location

Sacramento, CA

• Mar 22, 2013

• #3

1990JEEPXJ said:

Depends on the year of the new t-case. If its from pre-94 I believe then you are good. Has to do with the angle of the helical cut gears on the planetaries.

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It’s a t-case out of a 95 that I want to put my 21sp from my 88 into so sounds like I’m out of luck. I do have a part’s t-case I could yank the input shaft out of although I’m not sure the year of the rig it came from. It’s a 21sp np231J so if anyone could help me out with the year of jeep that t-case may have come out of id appreciate it.

 

Tim_MN

Freakish Hand Strength

NAXJA Member

Location

Minneapolis, MN

• Mar 22, 2013

• #4

Check the date code on the round silver and red ID tag.