My Motor Trike is a conversion on a 2006 GL-1800. I finally located the MT numbers on top of the differential near where the U-Joint is connected I used a mirror and took a picture with my phone. I sent the numbers and picture to MT. They told me the 2 in the first group of numbers was the employee ID of the trike builder. The 273 in the second group is 2.73 for the rear end ratio. The 3rd group is the date and year it was built. Being 6803 they told me the build was Dec of 2005. Look close to see the 3. See the picture.
