Friend swapped blown aw4 from his 97 xj with a good used aw4 from a 99. Puts it in, and it feels like its starting off in 3rd gear. Sounds like convertor is not locking up to me. I think his trans was a 42le and the 99 is a 43 le.

Any way to make this work? Not worried about a code/ light.
Thanks!

 

If I am not mistaken the 97 AW4 had a completely different transmission computer that is not compatible with the 98+ AW4s so it might have to be changed to allow it to work properly.

 

will a 99 TCU plug into the 97 harness? Does the acutall PCM (Computer) need to be changed also?

 

NO. I have a 98 one that would not plug into my 97;

Im sure there are searches on this here but from what I gather 96-older interchange with each other.
97 same as above except for one of the wiring plugs where trans plugs into main harness fix by soldering and splicing your plug onto donor tranny making sure to match the wiring positions between the plugs since wire color may vary year to year. dont use scotchlocks anywhere you have exposure to elements.
98+ 2 more wired in harness to trannny (I can verify this part personally when I tried a 98 wiring harness on my 97 recently)
97 has 5 wires; 98 has 7 wires, and a larger plug; NSS plug is OK its the other plug that goes to the solenoids etc

something about moving speed sensor and tone ring within the tranny is different on 98+ I remember a thread somewhere (dont remember which Jeep based forum) where a guy took the tail housing on and machined something on/for the outut shaft so as to be able to put a newer trans into a 97.

 

yup. I have one from a 98 sitting collecting dust. and a whole 98 wiring harness. only thing different between 97 and 98 is that TCM plug and the plug for the solenoids going to the tranny.

 

so how do i make this work?

 

BTDT.
The 98 has a 4 finger reluctor ring on the output shaft. You must remove it and install the reluctor from the 97 AW4.

The 98 has a both input and output speed sensors, the 97 had only the output sensor. The 97 TCU has no provisions for the input speed signal and the easiest way to eliminate that signal is to simply cut the wires.

The color codes for the wiring are different between the 97 and 98 so you'll have to reference the FSM's for both or trace each wire for the shift solenoids, output speed sensor and TCC (torque converter lock-up solenoid).

 

Great info,so it looks like he needs to get a 97 or older trans this 99 wont work in his 97

 

Not really.
The 97 can work with the mods I listed.