Thanks for posting this. You are the only one I've ever heard describe how these actually feel while driving. Much of it sounds very similar to the Borg/Warner ODs. I have never seen anyone use two speedos before but that is interesting to show what is happening before and after the OD.
Does it have a solenoid and governor system like the BW? It sounds like the "kick down" is more progressive than the BW which just takes the car out of OD when the accelerator in floored and back in when you let up. Studebakers had a hill holder that was a ball seal unit connected to the brake master cylinder and the clutch linkage.
When I looked under the pickup here with the Truckstell it looked to have several connections through linkage. This is cool old tech stuff.
