What's the main difference between the Aisin 8980 18 and the Aisin 8980 17 I got a trans from a 97 4runner with the 3.4 and hoping it will work in my 96 Tacoma with the 2.7 any help would be amazing the torque converter didn't seem to fit in the trans from the 97 and I know I have to get everything lined up

 

You'll have better audience over in the swaps section, and using the Toyota designation a340 97 vs 96..

In short iirc the pump is different and that requires the matching torque converter.