From Wikipedia
D4 is a revision of D3 created to underpin the Ford Flex and Lincoln MKT crossover SUVs.
Current D4 vehicles:
2009– Ford Flex crossover SUV — D471
2010– Lincoln MKT crossover SUV — D472
2011– Ford Explorer — U502
Ford Motor Company developed the CD3 platform as its first fully "digital" car, allowing the company to cut months of development time, saving money and bringing the vehicles to market more quickly.[1] Engineers were able to virtually build an entire car prior to initiating construction,[1] thereby improving vehicle fit and finish, tool clearances and production line ergonomics.[1]
Vehicles currently using this platform include:
2003–present Mazda 6
2006–present Besturn B70
2006–present Ford Fusion (CD338)
2006–present Lincoln Zephyr/MKZ (CD378)
2006–2011 Mercury Milan (CD338)
2007–present Mazda CX-9
2007–present Ford Edge crossover SUV (U387)
2007–present Lincoln MKX crossover SUV (U388)
2009–present Besturn B50
Cancelled CD3 products:
2009 Ford Flex crossover minivan (switched to D4)