Thank you very much for the helpful info from you good people

Fyi. Transmission was replaced because of coolant mixing with transmission fluid resulting in irreversible damage to clutches and other internal parts to the extent of grinding the input and output shaft bearings. I did not notice anything until it was too late. There was an emulsified oil/water mix when I checked the coolant reserve tank a few days before complete failure. What happened was that the transmission oil cooler line inside the radiator corroded letting pressurized coolant water in despite the radiator looking perfectly ok from the outside.

Hope this info helps others as well.