Which type of 231 transfer case do I have?

[MrBClark]

Which type of 231 transfer case do I have? Pretty sure its a 23 spline short shaft but not 100%. I have a 2001 Jeep 4.0 NV3550.

 

[AjRagno]

According to Novak, the NV3550 needed a long input gear.

 

[MrBClark]

According to Novak, the NV3550 needed a long input gear.

All I could find on Novak is that it is compatible with the 23 spline 231 but I honestly don't know.

 

[TWiG01]

Assuming all of your running gear is factory, you should have a 23 spline case. I THINK all manuals had 23 spline and autos had 21.

 

[SvtLdr]

I was under the impression that the 23 spline shafts came with the 6 cylinder and the 21 spline came with the 4 cylinder engines. I'm not sure about short vs. long shafts though...

I know @Lou is pretty knowledgeable on the 231 cases though.

 

[TWiG01]

I was under the impression that the 23 spline shafts came with the 6 cylinder and the 21 spline came with the 4 cylinder engines. I'm not sure about short vs. long shafts though...

I know @Lou is pretty knowledgeable on the 231 cases though.

That sounds right and would make sense. I just did some quick research and it seems that the 3550 requires 23 spline t case shaft

 

[Lou]

My 2003 4.0/nv3550 used a 23 spline short input.

 

[mrblaine]

I was under the impression that the 23 spline shafts came with the 6 cylinder and the 21 spline came with the 4 cylinder engines. I'm not sure about short vs. long shafts though...

I know @Lou is pretty knowledgeable on the 231 cases though.

The 30RH found behind the 4 cylinder takes the 23 spline input same as the 32RH found behind the 6 cylinder. Up until 03 the long and short inputs were for the manual and auto respectively.