Ummm.. Ok, Then I'm a bit lost. Shouldn't the torque converter have locked up as soon as you were at the necessary speed? You keep her in a heated garage ( room temperature, approx 22 C. / 72 F.), I thought the threshold for lock up being available was 10 C. / 50 F. / .. Or are there different specs for different models? JDM, USDM, etc.
I'd thought that if you'd routed the fluid through the rad first, that the fluid would have been exposed to coolant that was getting ambient air flow ( 32 F. / 0 C.), actually cooling down from "garage" temperature, while there was limited flow through the rad until the thermostat cracked open. But as you've routed directly through the cooler, this is obviously not the case.
Also, as obviously, I'm missing something here. Is the lock up temp signal from the transmission temp sensor or the ECT sensor?
Thanks,
Chuck.