I also think that you must have loosened in the vacuum circuitry that now causes you tranny not to work. But besides this if you say That means that you have inserted a heat exchanger in the secondary ciruit (in which the radiator is). This wrong....the heat exchanger should be fitted into the primary circuit, so where the coolant line comes out of the block towards the heating coil at one side, and at the other side where it comes from the heating coil at the water pump. So basically in parallel with the heating of the interior.
Having mounted it in the way I think you did, will prevent any heating of the SVO prior to the moment that the thermostat will open at 80-85 degrees.

Cheers,
Ingmar