Hello Soll
Did you have actualy a problem with the trans oil/ radiator?
This defect is quite rare, but it hurts. I already experienced it.

@ Buschtaxi.org (germanspoken-Forum) there are some oher Victims...
As repair I exchanged the radiator and all liquids - since then no further problems.
Take a look @ this solution:
http://www.hemmi4x4.ch/AutomatenKuehler.htm
this installation was selected because of high additional load and high cooling needed in the desserts of Africa on sandy underground - Not actually a Problem with the existant Radiator.
I recommend to you to close the connections of the ATF direct at the radiator and insert a separate oil cooler for the ATF Circle.
So you use the radiator onyl for the Engine cooling.
Greetings from the Swiss Alps
Tundra