Change from 4-speed to 3w/OD

A lot of manual transmissions that have a lower than usual first gear, that first gear is not synchronized. I know this is true with the older "granny gear" transmissions like the one in my truck, the Borg Warner T-18, as well as the NP435. This is why you cannot shift into first until almost stopped and also why you cannot speed shift them. They are simply not designed for it.

I do not know enough about the 833OD transmissions to know if first gear is synchronized or not, but that could certainly answer the question.