Taking cues from the sparse information provided, a terse reply:
1965 and later Saginaw 3-speed transmission had synchronized first gear.
It and the correct bell housing will fit the 235 but the transmission output is open drive (not torque tube).
There are 1st gear ratio options but final gear is 1:1. This you need to know to work with your current rear axle ratio.
To avoid calamity of a modified 3-on-the-tree setup, you would want a Hurst truck floor shifter, modified bracket and linkage. You have to make a new hole in floorboard.
Others will come along and give recommendations on the T5 5-speed transmission from an S10 but you specifically stated a 3 speed transmission of unknown year or make.
. I apologize, but I clearly confused everyone. I am asking can I change the 1946 4spd for a 1946 3spd directly. I’m not asking about going to a more modern drive train. The current 1946 4spd with the “granny low” 1st gear is a total non-synchronized transmission….on all 4 gears. The 1946 era 3spd transmission is geared higher and is synchronized on 2nd and 3rd. I’m asking can I go to an original era 3spd without any modifications. Is it a direct fit?
