Pontiac Repair: 2.2 sunfire engine trany swap, wiring harnesses, transmission work

Question
hi i have 2000 2.2 sunfire that has a good engine and auto transmission.  i want to swap this into a 1999 sunfire that had 2.2 engine and auto trany as well. The engine looks the same but transmissions differ.do i need to swap transmissions from the 1999 to the 2000 engine for it to work or will the 2000 trany work with minor changes to wiring ??? what all needs to be changed to make the 2000 transmission work.do i have to change wiring harnesses or can i cut and splice?? thanks for your help

Answer
Hey Dave:

if they look different they are different. one may be a 3 speed auto and the other is a 4 speed auto. they are not interchangeable. everything is different the harness the engine control module (computer) and the transmission mounting is all different. You need to find the same transmission out of the same year care with the same final drive ratio in the trasnmission. if you get one with the wrong final drive it will screw up the speedometer and the tranmission shift points if it's a 4 speed that you need. good luck :-}