Any reason a 89 model NP231 wouldnt swap right in place of a 96 NP231? Any differences is spline count, etc?

 

It most likely wont swap in. The input gear has different spline counts depending on the year and whether it came from an automatic or a manual. Let us know what type of transmissions the two transfecases are from.

 

The spline count may be different. But I think they are the same bwtween those years.

I know my 87 is different from my 89...

 

Both are on AW4s,

I know the 89s are mechanical speedo and mines electric, can the speed sensor swap over?

 

Doing some web research it appears they went 23 spline when they introduced the HO ? This correct?

Found another site that says 4.0s all had 23 spline ? Jeez

 

Here is the link most peope refer to: http://www.novak-adapt.com/knowledge...nput_gears.htm. However it is not accurate when it comes to length, but the spline count they talk about is accurate.

There are two things you have to think about. First is the spline count of the input gear, and second is the length of the input gear. Also they changed the way the gears mesh in the planetaries after 1994, so you can't just swap in your old input gear.

 

Looks like a NO - GO

 

So if i can find one Post what year, can I expect a 90% chance of a straight across swap? Cant afford much down time at the moment

 

Find a 91-01 tcase and swap in.