All 3-speeds lock up mechanically...some later transmissions in the 904 family have an electrical connection but it's for unlocking the converter only.
I cant see how that can be since the solenoid has to close the bleed (vent) in order for the lock-up valve to move so the converter can lock-up. I would consider them as an electronic controlled lock-up only because they have the PCM controlled solenoid. Even one of my Mopar 1986 training books calls them a "Electronic Lock-Unlock converter". Ron
