Tried the modulator thing, no fluid leaking.
I had the tranny serviced under what Chevy requires, so maintenance is up to date, and was doen when required.
The way it feels is like a stick, where it revs up, and you have to manually shift to next gear. You have to lett off the gas several times in order to get it to catch. Once it catches, it is fine.
I have suggestions of tranny pump, linkage and shifting mechanism in the tranny.