I am curious how complex a project for swapping an automatic transmission would be? I have a perfect candidate lined up, the car I want comes with a Jatco 4N71 4-Speed. But doing some research I see the very next generation of the same car was outfitted with a better Aisin 03-72LE.
Luckily the car I'm talking about is a Mazda Miata, and there was very little alteration done to the drivetrain between the first and second generations as far as I'm aware of, they are both 4 speeds as well. I would assume that pursuing this further I'd want to go speak to people with more specialist knowledge, likely on the transmissions or cars. But I'd like a general idea of the efficacy of the idea, I'm not even necessarily interested in more power, Just a more reliable transmission. I just want to know if this sounds crazy or doable.
Thanks
Speaking in general, an obstacle is going to be the computer network and modules in the car that are designed to work with the earlier transmission. That could be a real bear to sort out. There may also be physical and mechanical issues like differences in the bellhousing, crank, and shifter.
Possibly @Mod_Man would know specifics about the viability of this swap.
It would be a bigger headache than you think. The computers are different, wiring is different, etc. Unless you are willing to pay thousands of dollars making it all come together, I would not recommend the transfer.
Hypothetically, if I had a car with the normal 4-Speed and that trans eventually died, I wonder if there would be much of a price jump between installing a new donor or factory re-manufactured transmission vs paying maybe an extra 1k or so for the upgraded trans and work to get it fitted.
I know that alot of Miata owners like to swap the 5-Speed Manual from the 1st gens out for the 6-Speeds in the 2nd gens so there's certainly some precedent for it being doable. The complicated part it seems would be finding someone with the specialty and know-how to be able to do it.
Finding someone qualified would be the key...and it wouldn't be cheap to do.