Are the "early" 3.4 harnesses compatible w/ later 3.4's? I'm hunting down a 95.5 harness and ecu (5spd) I have also found a 99 or 00 3.4 auto engine. Will all that work together? My brothers trying to help me save my4rnr by helping me swap in a 3.4 so here is my start

 

from what i have been told, no they will not fit. 95.5-97 will inter-change but 98+ changed to what they call universal plugs.

 

I think that the Belize Off Road Team is correct. The first harness I tried to use was from a 97 T100 3.4 but was a 2wd unit and wouldn't work. The next harness I got was from a 98 T100 and it had a number of different plugs on it. I had to switch some of the sensors and the throttle body off a newer motor.

 

Thanks for the info. I will continue to try to find a full swap from the same vehicle instead of trying to piece things together. Sounds easier that way.