I have a DP70 that had the ECU bypassed for years for the high speed solenoid and was controlled by manually switching the toggle switch to activate high. I am trying to make it shift again the way it should. I replaced the ECU and it still does the same thing. It starts in high, and will automatically switch to low gear at speed. It is working backwards! When I test voltage to the high speed solenoid, it has power, the drops out when it should be shifting to high. There is 2 diodes at the valve body that test good. What am I missing? Should voltage apply the high solenoid, or should it drop to activate? When the ECU was bypassed, putting voltage activated the solenoid fine. Is it possible that I have the wrong solenoid for the high speed? I notice the parts breakdown lists a different part number for the high speed. Sorry for the long post. Thanks for any help! S/N# T20C60961