Transmissions

buckaroo kid

New member
I have a 89 YJ with a 4.2L. I have a 3 speed automatic. Question is will a newer 4 speed transmission work or am I stuck with the 3 Speed.
 

Careful, some of those newer trannies are controlled by the ECM. I don't know for sure but I'll bet all they had in 89 was lockup torque converters (anyone else know this for sure??). Later Jeeps had an extra connector on the ECM for the automatic, I believe. My 05 ECM only has three connectors (manual trans). All the automatics I've seen have four connectors. Be sure before you buy anything... Unfortunately, swapping things around is getting pretty hard as vehicles get more complicated. Best of luck - John
 
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