Hey guys, does anyone know if this will work? I have a 99 4x4 3.0L and I found a trans from an 01 4x4 3.0L for a good price. Will this trans work in my older truck?

According to my sources, all the Mazda trans are interchangeable (within the same size engine), and the Mazda trans started before 99, so you should be good to go. The only possible hangup is if the speed sensor is different between 99 and 01, which I don't recall.

Thanks, Rubydist. Appreciate the info. The tranny I have is a 4r44e, and the one I can get for cheap is a 5r44e. So mine is a 4 speed, and the new one is a 5 speed, but the extra gear is done through software apparently. From what I understand they are mechanically identical. But are they truly interchangeable? Or would I have to get a new computer or anything? Both are from 3.0 4x4. I dont want to buy it until 100% sure about this...no return policy.

No, that's a different story, because the pcm controls the shifts, and you would need the pcm for the 5 speed to make it work right. There may be other changes too - like the wiring to the pcm might be a little different, so you need to check out the wiring diagrams first to know if it will work.