Will a 2004 mercury grand marquis transmission fit a 2006 mercury grand marquis

Transmission numbers must match or it won’t work.

Transmission numbers must match or it won’t work.

It's usually best to go with what the vehicle was designed for but if the pan bolts , wiring disconnects and everything else match then it should work but you may still have a problem with the computer who knows . I would have the original rebuilt if you think an old car is worth it and it's not rusted out ..