I just picked up a 92’ SC400, and for the first 10 minutes of driving it’s perfect, shifts great runs great. After about 10 minutes I hear a whine coming from the transmission and no matter what gear I’m in the car will rev but won’t move. If I turn it off and wait about 10 minutes, the car will move in all gears again but shortly stops and the problem starts all over again. I have checked the fluid (warmed the car up put it in nuteral and pull the stick) I have dropped the pan, replaced the fluid and filter, I have tested a known working ECU, I have flushed the trans, and no matter what I do the problem persist. Any advice would be amazing. No Warning lights, no engine power issues, and I have used the correct ATF fluid from Toyota. I am at a loss and can’t figure it out for the life of me.