Here's why it's complicated:
* Engine variations: Both years offered multiple engine options (e.g., V6, V8). A direct swap only works if the engines are identical. Even if the displacement is the same (e.g., 4.0L V6), there might be internal differences.
* Wiring harnesses and computer systems: The engine control systems changed over the years. The 1996's wiring harness and PCM (Powertrain Control Module) likely won't be compatible with the 2000's system. This is a significant hurdle.
* Mounting points: While generally similar, there *could* be minor differences in mounting points that would require modification.
* Emissions systems: Emissions regulations changed between 1996 and 2000. The 1996 engine might not meet the 2000's emission standards.
In short: It's *possible* with significant modification, but highly unlikely to be a straightforward swap. You would need to carefully compare the engine codes and investigate compatibility of all related components (wiring harnesses, sensors, PCM, etc.) before attempting it. It's much more likely to be easier and less expensive to find a used engine from a 2000 Explorer or rebuild the existing engine in the 2000 vehicle.
