Tim you are right in the positions of the shifter. From left to right they are N 1-4 1-3 1-2 R.
I did some research on why they are called dual range.
Prior to 1952, the transmission provides four different control or operating ranges which may be manually selected by the driver through movement of the shift control lever at the steering column.
N - Neutral
Dr - For all normal forward driving
Lo - For maximum power forward, such as operating up steep grades or in sand and also to be used as a brake when desending steep grades.
R - Reverse.
The 1952 hydra-Matic Drive provides two forward driving ranges. (Hence Dual Range)
Dr - 1-4 for normal driving
Lo - 1-3 for driving in congested traffic and hilly or mountainous country.
The previous discriptions are for cars, the following are for trucks.
N - Neutral
1-4 - Normal forward driving
1-3 - For faster acceleration and in congested traffic.
1-2 - For controlled power - pulling through sand or snow, and when necessary to ascend and desend steep grades.
R - Reverse
A note of interest about the 1-2 range. "This position should be used to place vehicle in motion on icy roads as vehicle can be moved in 2nd with light to medium throttle... the second speed start is used on the 1/2 ton only".
The manuals have many more items of interest in them.
Therefore cars before 1952 had a single driving range for forward (1-4), 1952 cars had two driving ranges (1-4 and 1-3), and trucks had three forward driving ranges (1-4, 1-3, and 1-2).
The truck trans. was the same dual range hydra-matic as the cars with different valving to provide for the driving demands of a truck.
Curly I hope you are still reading, where did you get your rebuild kit?
Thanks for the posts.
Lonnie
