Swapping a YJ T-case into an MJ

[M1A1TankerTom]

I have a 89 MJ with an AW4 and a 21 spline 231 t case. Was looking at putting a 231 t case from a 95 YJ with a manual tranny into my MJ. Both are 21 spline, but I have read conflicting things online that they may be clocked different? Anybody know if this would be a direct bolt up or is modification required?

 

For info I'm looking at swapping because the YJ case has a 4:1 Tera low, HD chain, and a SYE kit.

[Rockfrog]

The clocking was done at the transmission ... The pattern in the tail housing was offset differently between XJ/MJ and the YJ/TJ.

The transfer cases were the same for all jeep vehicles, 242 or 231. Only the input gears were different, but rarely an issue enough to worry about.

 

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[DirtyComanche]

I don't think a 95 YJ should have a 21 spline output on the 5spd (AX-15).  It should be 23.  I could be wrong, since I don't feel like looking it up.

 

But as said, otherwise they are the same.  If it fits, it fits.

[Rockfrog]

All the 2.5L Jeeps retained 21 spline outputs (AX5), only the 4.0's switched to 23 spline outputs. I'm going to guess his 95 parts source YJ had a 2.5L engine.

 

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[M1A1TankerTom]

[Blue XJ]

Worst case, you could always swap the guts from the YJ into the MJ case.

[DirtyComanche]

Worst case, you could always swap the guts from the YJ into the MJ case.

 

Not with the TeraLow.  He needs the correct one.  It uses it's own front case half, input/planetary gears and whatnot else.  So if it is the wrong version (23 spline) he's hooped, you can't just swap the input or whatever else.

 

But as RockFrog says, if it's the 2.5L version it is 21 spline.  I always forget about the 2.5L.

[M1A1TankerTom]

It's a 21 spline for sure. I'm actually thinking about not going through with the purchase now. I think it's a good deal, but there is so many bad reviews about the Tera Low.

[DirtyComanche]

It's a 21 spline for sure. I'm actually thinking about not going through with the purchase now. I think it's a good deal, but there is so many bad reviews about the Tera Low.

 

Oh, it's a piece of garbage.  I wasn't going to say anything to bring you down, but seriously I would never even consider running one.

[Rockfrog]

X2 ... With the limitations they have due to poor input design, not on my wish list either.

 

And for the cost, there are several better options.

 

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[Blue XJ]

 

 

Worst case, you could always swap the guts from the YJ into the MJ case.

Not with the TeraLow. He needs the correct one. It uses it's own front case half, input/planetary gears and whatnot else. So if it is the wrong version (23 spline) he's hooped, you can't just swap the input or whatever else.

 

But as RockFrog says, if it's the 2.5L version it is 21 spline. I always forget about the 2.5L.

Good catch. I stand corrected. I knew the planetaries were different, I didn't know it had its own input.