904 has no first gear?
You will have verified that you have the info you need once this thing is all fixed; not before. And working with the governor is a chore; remove driveshaft, remove crossmember, remove tailshaft housing... I would like for you to be able to find the info you need in a service manual, but I'm crossing my fingers in hopes that you just get lucky on this one. I've dealt with lots of transmissions with stuck governors, and they almost always start in 3rd; not 2nd.