Why is coolant leaking into transmission

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your Dakota. Coolant leaking into the transmission is often due to a problem with the radiator's built-in transmission cooler. This cooler can develop an internal crack, allowing coolant and transmission fluid to mix. Even though the radiator was replaced, a manufacturing defect or improper installation could cause this issue. A failing water pump wouldn't cause coolant to leak into the transmission but might indicate a separate cooling system problem. Your mechanic should inspect the radiator and transmission cooling lines for any faults. If coolant has entered the transmission, it's critical to address it quickly, as this can damage the transmission. A transmission flush and repair to the cooling system are likely needed to prevent further issues. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!