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need help transfer case questions???

B

bartlett91

NAXJA Forum User
Location
York, Pa
Ok so im new to jeeps and just getting into them. I bought a 90 2door xj limited, and my transfer case ended up having a really bad crack in it. I ended up buying a np231 to swap into it i read alot about the swap and it seemed pretty simple. But i got the swap all done and went to try to move the jeep and it wont move just dont do anything... Im stumped can any one help me??
 
Is the transfer case properly engaged in gear, or is it in neutral ? What make, model, year, engine size, and transmission was the donor of the NP231?
 
231J came in 2 flavors

21 spline input - which is what your old one was

23 spline input - which, I'd bet dollars to doughnuts that you bought and installed, and is the reason it won't move.
 
If the input spline count was different he likely wouldn't have been able to bolt it up. Some years did have different input shaft lengths, if he put a short spline shaft on a long shaft transmission that may explain it. My money is on the linkage not being correct and it being stuck in neutral.

We'll see. Seems like the longer I live the more wrong I am!
 
I've seen it before, but it's been a dozen years or so since. I cant remember if it was a 21 on a 23 or 23 on a 21... one will slip over the other and not engage. Or, if it does, it lasts about 3 seconds.


The only other thing I can think is something went wrong with the trans....
 
90 automatic, right? Probably 21 spline.

The transfer case would be a 23 spline if it came from a 91 or later auto or an 89 or so (unsure of exact year) 4.0 5 speed. I believe all 4cyl manuals had 21 spline but not sure.

So basically your 21 spline trans output shaft is probably spinning freely in the 23 spline input shaft on the transfer case. What year donor was the transfer case from? What's the 8 digit part number on the red and silver tag on the back of it? It'll probably start with 52 or 53.
 
The transfer case came from a 91 it was in a yj with a 5speed but he pulled it from a xj and mines a 90 auto. But it cant be because of the linkage.. I dont have it hooked up i put it in 2wheel myself
 
Yeah damn do i feel like an idiot, luckily i have a buddy with a few 21 splines laying around. Hes gonna trade me, thanks for all ur help i really appreciate it
 
91 YJ with a 5 speed and 2.5, or 5 speed and 4.0? At least as late as 94 (I threw a new tranny in one Thursday, been there done that lol) the YJ 2.5 5 speeds (AX5s) still had a 21 spline output shaft and the 4.0 5 speeds (AX15s) had a 23 spline output shaft. I'm not sure if XJ/MJ AX5s that late had 21 spline or 23 spline, it surprised me a bit seeing a 21 spline in a 94.

Judging by the way it's behaving I would bet a 4.0/5speed donor and thus a 23 spline case.

Shit's confusing, especially when you throw in a donor that's different... I think we've all been there LOL
 
Ok well i got the jeep running now with the 21 spline tc and it runs great. But the only thing is is my speedo dont work, anyone kno whats goin on here?
 
You probably indexed your speedo sender or gear drive housing incorrectly, or left the VSS unplugged - I forget exactly how to do it but there are directions that can be found via google. It's a 5 minute fix.

I hope you had it too far back, if it was engaged too much or just slightly too far back it may have torn the teeth off the speedo drive gear.
 
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