98xj trans swap help

Alright, im new to this forum and need some transmission professionals here. I own a 98 xj and swapped the trans with one from a 97. The 97 and older trans don't have an input speed sensor. Therefore the computer is throwing a code and the check engine light wont go off. i currently need to get this inspected asap. ive tried numerous things. im leaning on replacing the tcm (transmission control module) with one from a 97 or earlier model that will read the trans without that sensor. Is this possible? or are there any other options? ive tried connecting the 2 sensor wires together, sticking a magnet on the end of the sensor, a piece of steel, grounding the sensor magnet, and even running a cordless drill with a steel bit on it next to the sensor. none of that has worked.

All AW4 transmission from all XJs require a speed sensor. Have yu tried plugging the sensor in OR is there a big HOLE in the tail housing where the sensor should be?

93gc40 said:

All AW4 transmission from all XJs require a speed sensor. Have yu tried plugging the sensor in OR is there a big HOLE in the tail housing where the sensor should be?

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You're thinking of the output speed sensor. '98+ added an INPUT speed sensor that is causing his problems.

OP, there was talk of TCU swapping in this thread that may help you out:
http://www.naxja.org/forum/showthread.php?t=1053970

Of particular interest to you is the excerpt from kastein's initial post:

kastein said:

UPDATE Mar4 2013 - :: user memasmuffn reports that installing a 1997 TCU (designed to work with the older 1 pulse/rev reed switch output sensor, and no input sensor) in a 98-01 XJ with a 97 and earlier AW4 swapped into it results in no codes! This is great news, any AW4 (2wd vs 4wd, 2.5L 87-90 vs 4.0L all-years, and 2wd 95- vs 2wd 96+ notwithstanding) can be bolted into any XJ/MJ with only minor wire splicing, hard-part/housing/sensor changing, and perhaps TCU swapping at the worst. Awaiting further testing from the field to make sure the code stays gone!

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You'll have to look through that thread for the details though.

Also, if you happen to need a '97 TCU, I have a couple on the shelf you could have for a reasonable price.

thanks for the link, ive actually read this prior to installing the trans and missed the part about the tcu, im picking one up from a local salvage yard today, and im gonna research the numbers on it beforehand. yesterday i found 2 97's in a upullit but both had a 98 tcu and trans for some odd reason. but i wil post results later on and wheather or not i need one. thanks!

and to 93gc40, theres no hole for an input speed sensor, the 97 and earlier models only came equipt with an output speed sensor, no input

A '00 next to a '97 TCU:


Two '97 TCU's: