I don't disagree with you or Gale Banks. However I have not changed the geometry of my transmission case like Banks did by installing a flat plate cover on the differential that he tested. Therefore I feel confident that fluid is getting to every area that needs it.

If Banks were to put this old diesel on the lift (that is if it didn't vibrate off and crush him) and had a window into an operating 717-400 then he would see some aeration, and probably some increased ATF temperatures just like he saw with his differential test. The increased drag might even result in lower kilometers per gallon on the road, but so far I haven't noticed any (still in the high 30's/low 40's in 5th gear on the highway).

For a transmission this old where many of the internal parts are NLA, a rebuild is an iffy proposition. I slight overfill on the museum car might not be appropriate but for this beast it's perfect fix.
Thanks for posting (I enjoyed the videos).

My point was the overfill could lead to aeration of the fluid / less actual lubrication. I'd also be concerned that oil would start to leak out of a worn input shaft and on to the clutch.

I consider things like gear rattle / whine , the slight smell of oil / fuel , solid lifter noise part of a older cars character, something sorely missed in modern cars.

You are welcome.