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Unread 07-06-2010, 01:47 PM   #1
motobob
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YJ to TJ transfer case swap

I was wondering if anyone knew what the differences were between the yj model np231 transfer case and the tj np231 transfer case. I ask this because I am in the process of putting in a yj np 231 into my tj. The differences I see so far are that the shifter arm is up instead of down, and that the yj transfer case is not fully open in neutral like the tj transfer case is. I am trying not to have to open these cases up. I am putting in this older model np 231 because it has a tera low kit installed in it. Thanks for the help.

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Unread 07-06-2010, 02:29 PM   #2
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I did some more research and found that the tj 231's have a true neutral, but the yj transfer cases do not have a true neutral. Do you guys think this will pose a problem being flat towed. Will I have to do anything differently now?
I still am trying to figure out how to connect the linkage though. any help would be great
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Unread 07-06-2010, 02:37 PM   #3
NorCalCon
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BigSquat has a build thread were he put a Rubicon Case in his YJ.
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Unread 07-06-2010, 02:44 PM   #4
NorCalCon
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http://www.jeepforum.com/forum/f12/r...my-yj-1014552/
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Unread 07-06-2010, 02:58 PM   #5
NotURMailman
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Yes, if you flat tow with the YJ t-case you will have to disconnect the rear drive shaft.
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Unread 07-06-2010, 03:28 PM   #6
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subscribed. I just installed a t-case with an SYE in my TJ, and I'm having problems. I looked at the tag, and it says it's a 1996 t-case, so I'm not sure if it's a YJ or TJ case...
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Unread 07-06-2010, 03:36 PM   #7
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Quote:
Originally Posted by NotURMailman View Post
Yes, if you flat tow with the YJ t-case you will have to disconnect the rear drive shaft.
Is this because I dont have a vacuum disconnect in my front axle? If you flat tow a regular yj you do not have to disconnect the driveline correct?

Thanks for the links guys but I am trying to go the other way from a tj to a yj transfer case. I switched all of the electrical but I am still trying to figure out the linkage. I just spoke to teraflex and he said that the linkage arm on the tj transfer case is clocked in a different position. I will try this when I get home. Any other input would be great.
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Unread 07-06-2010, 03:46 PM   #8
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the YJs use an internal slip yoke, while the TJs use an external slip yoke. better add a new YJ style slip yoke to your project list.

if it were me, i would pull the gets from the YJ case and install them into the TJ case, and also add a SYE at the same time. this way you do it all at once, you know it fits without screwing around with different linkages, and it will be a learning experience at the same time.

do it right the first time.
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Unread 07-06-2010, 04:46 PM   #9
motobob
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Originally Posted by MisfitSeven View Post
the YJs use an internal slip yoke, while the TJs use an external slip yoke. better add a new YJ style slip yoke to your project list.

if it were me, i would pull the gets from the YJ case and install them into the TJ case, and also add a SYE at the same time. this way you do it all at once, you know it fits without screwing around with different linkages, and it will be a learning experience at the same time.

do it right the first time.
Both t-cases have slip yoke eliminators already. I probably should remove the tera low and put it in my tj t-case. I am the one who originally installed it in the yj t-case so I already know how to do it. I was just trying to avoid it.
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Unread 03-11-2011, 05:54 PM   #10
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Sorry to wake up a dead thread. I'm in a similar situation. My 2004 TJ t-case has some issues and I'm pressed for time/money and a buddy of mine offered me a 1995 Cherokee t-case for pretty cheap. I was gonna do an SYE to it and just swap t-cases. Will I have any issues (vaccum?, electrical?) going from an '04 to a '95?
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Unread 03-12-2011, 10:31 AM   #11
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I think the elctrical will be the same. If I remember correctly the vacuum is different. If you can use the back half of your tj transfer case. Also use the shifter arm that goes into the transfer case from your tj. Another reason to use your tj inners is that a tj case has a true neutral where a yj case does not. In neutral on a yj case it spins both drivelines at the same speed.

This is all dependent on an xj case being the same as a yj.
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Unread 03-12-2011, 11:11 AM   #12
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Works for me. I put a vacuum operated YJ t-case with a SYE in my TJ with no problems... direct fit other than the electrical connection swapped out where the vacuum was.
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Unread 03-13-2011, 09:37 PM   #13
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Quote:
Originally Posted by Luv-My-TJ View Post
Works for me. I put a vacuum operated YJ t-case with a SYE in my TJ with no problems... direct fit other than the electrical connection swapped out where the vacuum was.
Yes it is a direct fit but the internal are absolutely different. The yj doesnt have a true neutral. The tj does. It is better for flat towing to have a true neutral. Also the arm that shifts that transfer case is clocked 180 degrees off.
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Unread 03-13-2011, 09:45 PM   #14
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If you decide to still put that 231 in the tj out of the yj hit me up with a pm, I would be willing to sell you the stock output shaft for cheap as I recently installed a sye so it is just sitting collecting dust.
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