One problem related to radiator has been reported for the 2008 Dodge Ram 1500. The most recently reported issues are listed below.
For several months, while driving the truck, it would try and go into 4w drive low. We changed the actuator and it seemed to work for about a week. Then problems became worse. Again it would go into 4w drive low while driving. But also when we stopped at intersections it would move at all. We would shut the truck off then it would go. We would hear a whining sound after the truck was shut off about 30 minutes coming under the truck. The end of July we had to change the fuel pump. Then we had to change the radiator and thermostat. We had it at 3 different mechanics before finding the problem of it going into 4w drive low. It was the timp and the transfer case. We have had to replace the actuator 3 times.