I just remembered another feature of the old overdrive transmissions. It has been nearly 50 years since I had that old 55 so my memory is not that clear.
That feature was “freewheeling’. If the transmission was in overdrive and you took your foot off the accelerator, the car would basically act as if it was in neutral. If you needed to use the gears to decelerate you had to take it out of overdrive.
I am not sure why but probably it was necessary for the overdrive to work properly.
That old 55 would fly. I remember it had a top speed of 110 and it would do that in 3 different gears. 2nd and overdrive, high, and high with overdrive.
My best friend’s Father bought a new 63 galaxy 500 with a 352 and a four barrel. We had a drag race and the old 55 beat it pretty easily.
A friend of mine had a Studebaker Hawk with an overdrive knob on the dash that had to be pulled I believe. I have no idea how it worked. My only idea as to how it worked was that it was in the rear end and not the transmission itself. But that’s always just been a guess
Galaxy was not a slow car.
I am curious about the “freewheeling” effect. I think this was just an effect of having a very high(low numercally) gear ratio, but not really a “slipper clutch” type of effect. I would say that most likely if you were in first gear, you would have the engine braking effect even in overdrive.
At least I don’t remember any slipper clutch like action from the old overdrive trannys.