You are correct about the Ds trans computer. I compared its design to that of the the ZF4.Bosch computer. I really like the Ds design because of its simplicity. It is most likely that the voltage comparitors are failing. The problem though is converting to an Eprom of PLC controller. You still need an input signal and some logic to control when to shift. On later computers this in programmed into memory. The after market computers now available are about $1000. 00. still way too expensive compared to a $400 D computer unless you are looking at lifetime costs. The question is whether isolating the chips in the car would make them live longer. Or are voltage spikes killing them. I know on my transmission, we have had voltage spike fry the pressure modulating circuit twice. We had to building an isolating circuit to protect the computer. Bob