Aw4 help 2wd to 4wd conversion

Those of you who have done it, what did you do with the wireing? We got everything in but CEL is on and it's not shifting, I have a 97 and all my doner parts are from a 98 Made a make shift wireing harness the trans on the 97 had a 6 pin connecter and the 98 has a 8 pin. CEL seems to be the speed sensor, is there anyway to bypass the speed sensor on the 98 trans? Squirrel80 is helping me out on this we thought we would see what other people have done. Thanks!

That's the problem... the 98 speed sensor puts out 4 pulses per revolution while the 97 only put out 1, and the signal is different. You can build an adapter if you can solder a little, lawsoncl posted a schematic for the one he built. I know he posted a very useful explanation and some pictures, but all I can find is the PDF with the schematics: http://mysite.verizon.net/~chris83803/AW4_Sensor_Converter.pdf

You can also change out the tail housing, sensor, and rotor (I believe Frank Z's build thread shows how to do this) but I found that more difficult, the snap ring holding the rotor on is very annoying and the rotor was a different thickness on mine so I just went with the electrical adapter, since I work with electronics a lot anyways.

We are trying to avoid the tail shaft swap if at all possible but thanks for the heads up we have been messin with the wireing all night and just decided to call it a night hopefully tomorrow we can figure something out. Split years suck!

Forgot to say that I have the wireing harness from the 98, we haven't found anything usefull on it except the trans connector that we used to make a make-shift wireing harness so the plugs would connect and didn't use 2 out of the 8 I forget what ones we didn't use cause I don't have the jeep sitting here to look.

OK I'm am helping with this swap. Where do you get a pulse divider that is useed in this diagram.

Or what about a '98 trans computer would that plug in. This is a little above my wiring skills.

tone said:

We are trying to avoid the tail shaft swap if at all possible but thanks for the heads up we have been messin with the wireing all night and just decided to call it a night hopefully tomorrow we can figure something out. Split years suck!

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You don't have to swap the shaft, just a rotor snap-ringed onto it and the metal housing that goes around it, plus sensor. Yeah, it's going to be a pain in the arse to do now that the transmission is installed in the Jeep.

You COULD install the 98 TCU, but I see two possible snags -
* the 98 TCU may get really unhappy about trying to talk to the 97 ECU. I don't think it will, but it may.
* the 98 TCU will expect the signal from the input speed sensor as well (the one right up near the shift selector cable) so you may have to run one or two wires from the transmission wiring harness connector by the tranny dipstick tube to the TCU under the steering column. It's only like 12 feet of wire, if you don't mind doing it, go for it. You will want the connector for the 98 TCU at the very least, since you'll need to pull one or two pins out of it and insert them into the 97 TCU's connector in the right cavities, then plug the 98 TCU into it. This may be more difficult than swapping the entire engine compartment wiring harness and dash wiring harness, but I don't think it will be.

If you can verify that the 98 TCU will peacefully coexist with the 97 ECU, this gets a lot simpler. Adding the wiring for the input speed sensor should not cause problems with using a 97 TCU and a 1pps (97-down) output speed sensor + rotor in the future AFAIK, so it's worth a try I guess.

A 97 FSM and a 98 FSM will GREATLY aid you in doing this wiring. I don't know the wire colors offhand for the input speed sensor, else I'd post them up for you.

Connected the input speed sensor from the trans to the '97 computer and the trans is shifter very well. It has a slightly higher shift point, but nothing abnormal. It did trigger a CEL but will work for now untill we can tear it apart and correct the problem. I will probably try and find the correct trans for it later. It works great for now.