OK ,, so what you are saying is that I need a transmission rebuild..
you dont think that it could be an ignition problem , or an over voltage problem with the alternater, or a problem with the ignition module?
Why when the hesitation is happening, I press down on the gas pedal and the engine does not respond ?

It would not hurt to get it rebuilt now if you can, I do not know a lot about transmissions yet, but given what little I have learned I'd suggest getting it rebuilt soon, rather then to wait and chance the transmission failing from lack of that 4th clutch thrust washer.
What that washer does exactly I do not know, and am wondering myself, as I found that same material in my transmission filter.
I'll have to wait to fix my car though, as a transmission rebuild is not in my budget yet.
If one is not in yours either I hope yours holds together till you can get it rebuilt.