The little 'Trigger' on the Gear Shift, is a Reverse Lock Out, so you do not accidently elect 'Reverse' when shifting Gears.
It is a four speed non-Synchromesh Transmission, and low is 'Compound Low'.
That is a very good Transmission, my 1946 one ton had the same Trans, and I really liked it.
If memory serve, Reverse is to the left, and back, and you have to pull in the little Trigger' thing.
