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AW4 to AW4 tranny swap


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So I got a an '87 MJ 4.0 4x4.  The transfer case needs replaced/rebuilt, but I have a '96 parts XJ that I figured I can just take out the tranny and tcase.  Both have a lot less miles than what is currently on my MJ.  I was looking at the "Everything You Ever Wanted to Know About the AW4" post and it says 1990.5 - 96 are bolt in.  Is there any thing with the electronics that I am going to have to change out as well?  Also, any other tips are appreciated.  This will definitely be my biggest vehicle project I've ever done, but I will give it a whirl, hopefully this weekend.

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Literally just did this last month. Swapped a 95 aw4 and 231 into my 88 MJ. Straight bolt in swap, besides a couple small things

 

Speedo cable housing will need to be swapped in place of the electronic plug.

 

The shift arm on the Aw4 will need to be swapped due to different angles

 

Otherwise its straight forward, Id recommend changing all the seals you can while everything's out and easly accessible and a new torque converter isn't a bad idea as well as check your flexplate on the engine for cracks. The only downside after the swap is you will lose your "part time" indicator light, I'm not sure if theres a way to keep that...Otherwise take your time, hire a friend or 2 for the day and dig in!

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The only downside after the swap is you will lose your "part time" indicator light, I'm not sure if theres a way to keep that.

The reason you lose it is because your MJ's part-time light is switched by the CAD vacuum stuff. The later tcase harness (sans CAD) should plug in where the older one does (connector at the trans dipstick / passenger side rear head) and you should regain that function.

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I was pretty sure it's the same for an HO and Renix, but I'm not sure. It runs down along with the trans harness, as though it was part of it (but it's a separate loom) and I'm pretty sure it also has the vacuum lines running along with it. If you just got the tcase by itself, my guess is the harness got left with the trans. I've got some pics and stuff, also a 4.0/aw4/231 sitting on the ground out back. If I remember this weekend I'll try to get them up.

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  • 3 weeks later...

Literally just did this last month. Swapped a 95 aw4 and 231 into my 88 MJ. Straight bolt in swap, besides a couple small things

 

Speedo cable housing will need to be swapped in place of the electronic plug.

 

The shift arm on the Aw4 will need to be swapped due to different angles

 

Otherwise its straight forward, Id recommend changing all the seals you can while everything's out and easly accessible and a new torque converter isn't a bad idea as well as check your flexplate on the engine for cracks. The only downside after the swap is you will lose your "part time" indicator light, I'm not sure if theres a way to keep that...Otherwise take your time, hire a friend or 2 for the day and dig in!

So I have the transmissions out of my MJ and my parts XJ, and I just haven't had time to mess around with it and install the "new" tranny.  What seals and other stuff should I replace since the trans is out?

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Torque converter seal, output shaft seal on the transmission, input and both output shaft seals on the transfer case.

 

Also would be a good time to remove the pan and replace the filter on the transmission since everything is out in the open if you'd like.

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