The parts of the TC tha tmake the car move are hard mechanical componants and therfore cant work intermittanty.
This is not the correct way to check the fluid and you could be low since your checking it incorrectly. The only way to check the fluid is to overfill it and then drain it down at 30C till the stream starts "gurgling".
You have to understand that there are pressure exhaust ports on the valve body. These ports are jetting fluid into the "pool" of fluid that sits in the pan. These jets make "waves" in the "pool". Therefore when fluid starts "trickling out" you could be just seeing the top of a wave trickling out.
Overfill the trans then warm it up to 30C then start draining out of the check port. Watch as it drians with a steady stream. As soon as you see the steady stream "gurgle" then plug it.