No, it's highly unlikely a transmission from a 1999 Dodge Grand Caravan SE will fit a 1996 Plymouth Voyager, even if they have the same engine. While they share a platform and may have used similar engines, transmission designs changed over those three model years. There are subtle, but significant differences in bellhousing bolt patterns, output shaft lengths, and internal components. Forcing an incompatible transmission could cause serious damage to the vehicle.
You need to verify the exact transmission codes for both vehicles (found on a sticker on the transmission itself or possibly in service manuals). Even with the same engine, the transmissions will likely have different part numbers and will not be interchangeable.
