93 aw4 into 87

? is will the tcu be plug and play or will i need to do something , i just want the spline upgrade in the newer tranny so i can run a diffrent case ,

The FSM shows the same wiring harness connectors and pinout for the NSS and tranny solenoid connectors on passenger side of the firewall. Based on that I'm 80% cetain the wiring harness on the 93 donor will plug right in and you don't need to mess with changing the TCU. If they don't mate up, use the NSS from the 87 and drop the pan to swap the solenoid wiring harness over (or cut & splice).

The 93 and 87 TCU are virtually identical with the exception of the diagnostic wiring being odb-I instead of a serial connection to the big yellow plug under the passenger side of the hood. The TCU connector may have changed with the switch to odb-I from the renix setup too. The 87 TCU should work just fine with the 93 AW4. You'll only have an issue if you try to use a tranny newer than 96 as there were some sensor changes.

The only other change on the AW4 between those years aside from spline count, is the 4th gear ratio changed slightly from 0.79 to 0.75 (in 1991?). The TCU won't care, but you might notice the 4->3 downshift is about 100 rpm off from before.

it will interchange just fine; plug and play. the spline count and OD ratio (.705 to .75) is the only change.

lawsoncl said:

You'll only have an issue if you try to use a tranny newer than 96 as there were some sensor changes.

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Does that mean the change was made in 97? or are some 96s diffrent too?

Jesse

lawsoncl said:

The only other change on the AW4 between those years aside from spline count, is the 4th gear ratio changed slightly from 0.79 to 0.75 (in 1991?). The TCU won't care, but you might notice the 4->3 downshift is about 100 rpm off from before.

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I think you meant 0.70 to 0.75 O/D (lower geared for less speed)

carnuck said:

I think you meant 0.70 to 0.75 O/D (lower geared for less speed)

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You're right. Not sure if I fat fingered that one, or I was thinking of the AX-15 which has a 0.79 5th gear (might have been since I went from an ax-15 to a later AW4). So yeah, 23 spline are 0.75 and 21 spline are 0.705.

noresttill said:

Does that mean the change was made in 97? or are some 96s diffrent too?
Jesse

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1996 was a oddball year with some vehicles being a mix of 95 parts and 97 parts, so I honestly don't know. The easy way to tell is to look and see if you see the front input speed sensor which was added in 1997. It's about half-way up the drivers side just behind the bell-housing. The rear speed sensor also changed from a magnetic reed type sensor at 1 pulse/rev, to a hall effect inductive sensor at 4 pulses/rev.

thks guys

thanks

lawsoncl said:

The 93 and 87 TCU are virtually identical with the exception of the diagnostic wiring being odb-I instead of a serial connection to the big yellow plug under the passenger side of the hood. The TCU connector may have changed with the switch to odb-I from the renix setup too.

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Minor update. I have the AW4 tranny computers from an 88 XJ and 93 XJ sitting in front of me, ready to go on eBay. The connectors are physically the same size and pinning. They look identical except the key on the connector is different. If you wanted to swap the TCUs between Renix and ODB-I, you would need to take a razor and shave off the raised ridge (key) on the wiring harness connector to get them to mate up. The 93 connector is green versus the 88 being grey, but I doubt that makes a difference.