This gear system was used in 8448 & 8466. I just built it a little smaller. It has 5 speeds plus reverse. If you have any questions or ideas please contact me! Details: -Blue joiner should be connected to the engine and white joiner should be connected to the differential. Contact: http://legoadam.turklug.com/iletisim.html Links: http://brickforge.de/software/brickstore/ - you need Brickstore to view the inventory file.