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Unread 02-19-2014, 06:31 PM   #1
aviationofficer
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1987 YJ Wrangler 
 
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NP231 Question

I've got an '87 Wrangler. I want to replace the original NP207 with an NP231. I found one out of a 2002 Wrangler that comes with a SYE. Will it work in my '87?

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Unread 02-19-2014, 06:58 PM   #2
jsipe007
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I believe it is possible but I am not 100% sure. If it is we are going to need a bit more info. What transmission do you have and what was the 231 mated to? There are many different input shafts for the 231 family.
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Unread 02-19-2014, 07:11 PM   #3
aviationofficer
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Sorry about that. I have a TF999 which i believe has a 23 spline output shaft. The t-case i'm looking at is also for a 23 spline.
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Unread 02-19-2014, 07:26 PM   #4
superj
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Yours had a 207? Mine has a 231 stock on the tf999. You checked the tag? I thought I had a 207 till I actually got under and looked at it
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Unread 02-19-2014, 07:37 PM   #5
aviationofficer
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Yeah i checked the tag. I thought it had a 231 till i looked.
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Unread 02-21-2014, 10:25 AM   #6
aviationofficer
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bump
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Unread 02-21-2014, 10:32 AM   #7
jsipe007
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1994 YJ Wrangler 
 
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I dug up this link. Might be helpful.

http://www.pirate4x4.com/forum/jeep-...gth-tf999.html

If the spline count is the same I can only imagine length being the issue.

Here is another link

http://www.bc4x4.com/faqs/yj.cfm?cat=6&faqid=141
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Unread 02-22-2014, 09:57 PM   #8
jeepguy85
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Quote:
Originally Posted by aviationofficer
Yeah i checked the tag. I thought it had a 231 till i looked.
If you can, separate them and count the number of splines if you are not 100% sure. IF it is a 23 spline input, run it unless you plan on an SYE. The only advantages a 231 offers over the 207 are better aftermarket support for SYEs, etc and a 2.72 gear ratio vs the 2.62 on the 207.

EDIT: I just reread your original post. The 87 uses a mechanical speedo. The 2002 TC will be electric. If the spline counts match up, you will still need to adapt the new TC to a mechanical speedo setup.
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