I ride a 05 zx6r. It has 18k on it and 2cd gear is going. My dilemna is that I found a good price on a 03/04 transmission with low miles but it has come to my attention that even though 03-06 are all 636's but they have little engine and transmission differences. I have done a little research and comparing part numbers there are some differences in the parts numbers on certain gears. For instance the output shaft and driveshaft have different part numbers between the years but the low output sprocket, low output gear and 2cd input gear have the same number of teeth and part number. The only other difference I see is the tooth count difference in 3rd and 4th on the ouput shaft. So is this possible, has anyone done it before? Just wondering before I buy it.