Beefing up A500 overdrive
Wrong. I never seen anything, other than alot of beating around the bush about the subject.
You saying centrifugal force and running in fluid is a non factor in the amount of power a given trans takes to operate? And that it doesn't take fluid pressure, from pumped-in fluid, to keep a clutch pack engaged?
Going from memory, the pump is relieved at ~275psi. All circuits are independently pressure regulated, except reverse, which runs wide open. Generally, the line pressure operates in the range of 55 to 90 psi. The TC at 30 to 75, lower in Neutral/Park. The lube line runs ~5 to 30psi. The governor at UP TO line pressure. Of all these circuits, only the lube-circuit is a designed-in controlled leak.
When the parts are new, there is very little oil leakage out of the power-pistons and or servos. The clutches are lubed by a different circuit thru tiny orifices running at modest pressures. When a clutch is disengaged the fluid is relaxed into the manual valve, about IDK say 1.3 inches from the bottom of the stock pan.... well below the spinning parts. The servos dump at a similar height. The bulk of the fluid that is being flung about is that which is semi-continuously leaking from the lube circuit, that has done it's job of lubing, including lubing the clutches, and which exits the drums, and mostly when the packs are relaxed.That exiting oil becomes splash-fluid for the bands, as they receive no other.
The pump and the TC are the only parts that are connected to the crank, until a clutch is engaged.
So you are correct;
It takes power to spin these parts up, just as it takes power to accelerate the vehicle;
But not much power is required to maintain speed, such as when cruising.
IMO
the power loss to the fluid is minimal, and not much can be done about it, anyway.
I think, the Convertor is the power sucking monster, lol, and the loss is directly related to the rpm and the load. After all, it is not coupled to the driveshaft in any way, but by anything other than the friction between the oil molecules.
For the OP none of this matters.