AW4 91 to 92 Electrical Changes? -
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Unread 06-03-2012, 10:02 AM   #1
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AW4 91 to 92 Electrical Changes?

I'm planning to convert my 91 MJ from 2WD to 4WD and am working on determining the correct transmission to get.

The 91 is an auto, so I would just plan to use an AW4 from a 91 MJ and call it at that.

However, I have a NP231 from a 97 XJ that already as an AA SYE on it which I would like to use. I know the electrical connections for the 97 AW4 wouldn't work. But I see that the AW4/np231 went to 23 Splines in 1992.

So I am trying to determine if the transmission electronics changed between 91 and 92 such that I would have problems trying to swap in an 23 spline 92 AW4 to match my '97 np231.

Can anyone help with what years saw what electrical changes for the AW4 transmission?



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Unread 06-04-2012, 02:23 AM   #2
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i don't know of any electrical changes on AW4s at all. Every one I have ever seen has a 3-solenoid valve body with the same solenoids for all years.
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Unread 06-04-2012, 02:38 AM   #3
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There were a numerous updates and changes to the AW-4 and to the engine computers that operate it, over the life span of the Cherokee/Comanche. Some of the changes can be dealt with for transmission swaps, and some cannot, depending on the exact transmission and vehicle in question.

1990.5 to 1996, the AW-4 will interchange with no problems. The 97 NP 231 should fit and function, but you will have no speedometer due to the difference in speedometer output, mechanical vs. electronic. You may have Computer and/or shifting issues due to no speedometer output to the computer. The best solution would be to install the SYE on a 231 compatible with the 1991 engine and transmission controls/computers.

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Unread 06-04-2012, 09:58 AM   #4
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Thanks Tim & Merlin. Sounds like I've got a reasonable path.
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