Trans low gear set.

[Adger Smith]

I would say your conclusions about the converter were correct. It was telling you it was too tight. It was probably on the verge of too tight with the other trans ratio.
The gear ratio made nothing, but tree/lite problems. You fixed it with a variable stall controled by "The Left Leg" Now it is loose any time you want or need it!! :~) But now: how about that gear ratio??