Jack, hang in there and try to find some patience to help educate us when we go astray. I seek enlightenment -- and guidance from a master is most valuable. You have the credentials to qualify as a master of the Hydro. I appreciate that and I will listen. However, I don't always accept what the master tells me without questioning the underlying principles.
My practical experience is from way back when I was the transmission guy in a Pontiac/Buick/Cadillac dealership. But the last dual range Hydro I had apart was in 1963 when I was 20 years old. Getting headaches from exhaust gasses in an enclosed garage caused me to find another profession. I have enough experience to know that I can't take a dual range apart and understand it by looking at the parts -- like I can with a standard transmission. Understanding an automatic transmission takes more than practical experience.
I understand well the principles and operation of a planetary gearset. I have studied the principles of operation of the dual range Hydro. I have studied the parts in the Hydro planetary gearsets using the Master Parts Catalog. So my experience is primary book learning and I have the mathematics and physics background to understand principles and design. I appreciate and listen to those who have the practical experience.
I had previously accepted that the dual range was "locked" in third/fourth. But when the disagreement came up, I studied the operation of the trans to validate that we were correct. The problem is that in that study, I could find no way possible that any two gears in the rear planetary gearset could be locked together without going through the fluid coupling. I did find how the ring gear and sun gear were "locked" but the sun gear was attached through the fluid coupling. I explained it in a document available over on the
new thread and I invite you to go over there, read my explanation, and tell me where I am wrong -- which I may be. Or just tell us how you believe two elements of the rear planetary are locked together in third/fourth.
I suggest further discussion be done over on the other thread where it can be found later by our ancestors wishing to learn about the dual range Hydro. It will get lost here in this thread.