swapability between S10 and cherokee NP231...

so i've been working on this S10 blazer and have come up with an extra NP231 t-case if i want it. i'm just not really sure what all may be different between the t-cases. isn't there 2 different spline-counts (27 vs. 29)? i would really like an extra 'case to build (with 4:1 and 2-LO) without having to disable my jeep...

depending on the year there may be some parts in the S-10 NP231 that you might consider swapping into your 231. A wider chain (1 1/4 vs. 1" wide) and a planetary with 6 gears vs. the typical 3. See this article:
http://www.madxj.com/MADXJ/technical/technicalfiles/JAtCaseUpgrade/tCaseUpgrade.htm
'94-96 were supposed to be more likely than other years to have these parts. No way to tell (afaik) without opening the case.

Here's another good article from Novak on the 231. It mentions some of the differences between the Jeep and GM/Chevy types.
http://www.novak-adapt.com/knowledge/np231.htm

Is it actually an NP231 and not an NP233? The NP233 is a 231 with an electric motor that moves the shift fork from a button on the dash. I just picked up a '93 NP233 that has the wide chain and a 4 gear planetary. When I do my SYE I'll see if I can swap in the chain. Not sure about the planetary. I suppose 4 is better than 3 assuming the gear teeth in the case match the new planetary gear teeth.

Don't know about stacking them, someone else will have to chime in.

thanks for your help...

wow i never knew that teraflex ESS kits were built by Novak. and i even worked at teraflex! i imagine that a 6 gear planetary and 1.25" chain would really add to the already-decent t-case.

bump

sorry i just wanted to hear what some other people thought about the subject...

Drivetrain direct has some tables that describe the transfer cases used with different models of Jeep, Chevrolet and others.

http://www.dtstulsa.com/transfercase/chevrolet.asp

You are correct as to different input spline counts. 27 input for Chevy vs. 23 or 21 for Jeep 231's.

There are also different lengths of exposed input shaft on the Jeep version (which may or may not matter,) and probably some wiring differences as well. You didn't mention if the one you have is a mechanical shift or the electric shift but that's possible. The table above also describes the front output on the Chevy 231 as being either a yoke or a slip output (?)
The Novak site also indicates that there were different bolt patterns for the transfer case to tranny between the Jeep and Chevy versions.

Probably the reason there hasn't been much response is that there are enough differences between the versions to make it very unappealing compared to finding a Jeep 231 and avoiding all the issues. Even free isn't good enough sometimes.