I have a 2000 3.0 4x4 auto trans Ranger that was my first truck years ago. Over the years it's seen a lot of use and abuse in 148k miles, but the tranny is pretty shot, (input shaft speed sensor code) and I've already replaced it once when my original one blew the front pump apart. I know someone with a 2007 3.0 4x4 with a rusted out frame, but only 64k miles on the truck. I know I could just slap the tranny in from the parts truck and it would work (for now), but my ultimate plan is to swap the whole drivetrain over from the 07. While the drivetrain is out of the 2000 I want to sandblast the frame as much as I can with my small blaster tank, and take care of some rust issues of my own. What issues might I run into with this swap? I know the intake manifold and fuel rails are different between the years so I plan on using the original. My 2000 is a flex fuel and I am unsure of the 07. I have 0 welding skills soI'd like to avoid removing the core support, but I am capable of pretty much anything else that can be accomplished by one guy with air tools and an engine crane. This would be my first engine swap.

 

I see no issues

As long as you swap over the 2000 upper and lower intakes with injectors to the 2007 engine it will work fine
The main difference that matters with flex fuel is the computer and injectors
The head differences are not an issue

The 2007 automatic will work with the 2000 computer, but not visa versa
2001 and up automatics have 2 extra sensors on the outside, they will be left disconnected as the 2000 computer can't use them
The 16 pin connectors are the same
Remove the DTR sensor from the 2000 trans, that's the sensor on the shifter arm/rod on drivers side of trans, compare it to the 2007 trans DTR, if connectors are the same then you have a spare DTR, if not swap it out

The 2007 trans is a 5R44E and 2000 4R44E, but internally the same transmissions, the "5" speed was done in the computer, OD on in 1st for a faux 2nd gear
So the 5R44E will be a 4R44E using a 2000 Ranger 3.0l computer