I have a 93 Chevy Silverado. I just recently rebuilt the transmission.for two weeks after the rebuild, it ran perfect. Then it started slipping in first and second. We tore it down, all clutches and seals looked good replaced all solenoids and accumulators, went through the valve body put it back together and the same thing. Did a line pressure test and was good. Playing around, l discovered that if I unplug the wiring from the trans while the engine is running the plug back up, the trans will work perfect until key is turned off.