Greetings!!
I need help!!! I have a 1999 jeep Cherokee sport with automatic transmission problems, the gear change (4th) does not work, the two mounted transmissions have the same problem, the input speed sensor registers data, but the output sensor does not register anything, they were tested differently sensors but none registers the output data, the changes from 1st to 3rd change well and strongly. Change the computer but still have the same problem. thank!!!!

you tested the sensors off the jeep, or on the jeep? it might be the wire to the output sensor is messed up somewhere between the sensor and the computer

Is this the original transmission, or was an older transmission installed?

Thanks!!!
The transmission (Replacement) have been tested on the jeep, the electro mechanic supposedly checked the cables between the computer and the sensor.

not all year XJ are fully compatible without alterations

there is an existing guide

if you google Jeep XJ AW4 year compatibility, or search this forum, you will find it

https://www.naxja.org/forum/showthread.php?t=1053970
Short answer is you need a 98+ transmission. If it's missing the input speed sensor on the drivers side near the front by pivot for the shifter cable then it's not a 98+ and it's not going to upshift out of 1st until the rpms are really high..