Near as I can tell the 722.6 never got electronic level reading, just a temp reading for transmission over load and accurate dip stick readings. My 97 has the temp sensor and the HHT can access trans temp.

The temp sensor is not active when in park / neutral from what I recall as it is part of the neutral safety SW circuit. To build temp, apply the parking brake, press service brake , select drive, then bring engine up to 1500 RPM or so. This will build heat in the torque converter.