2-wheel to 4-wheel interchange?

You would need to change over a few parts like the output shaft and swap over the adapter as well as a few other parts. However, you would need the transmission from a 1997-2000 Ranger with the 4.0 at a minimum. As such you would have an easier time just getting one from a 4X4 to swap in. If the rest of the truck is in good shape you can get a fully rebuilt and upgraded unit with a warranty for around $1,500.00.

Thanks for the help, Steve. I was afraid of that. I think I will find a 4x4 transmission.

You're welcome. Yeah, the conversion on some of them is rather involved, yours isn't as bad as many of the newer vehicles though. However, it's usually easier to just find a bolt in.