An automatic transmission will not stall an engine, unless the torque converter locks when is should not.

An idle speed control actuator that does not act fast enough to keep up with the rpm drop when cold, or a sensor that does not sense engine rpm properly, will allow rpm to drop until the engine stalls.

The engine computer senses idle speed, and controls it to keep a constant rpm. The transmission is just another variable load, like the A/C compressor, power steering pump, and alternator as far as idle rpm.

I don't know the specifics of how the idle speed is controlled on this engine, but your technician can check it.

Best Regards,

Jim