Cadillac Repair: transmission fluid going into coolant system on 1997 cadillac deville, how do we fix it, transmission oil cooler, coolant system

Question
how do we fix this problem? Is the radiator the cause? The problem again is the transmission was being changed at instant lube after it appeared to be fine. Found out that the transmission fluid is mixing in the coolant system. What was the cause?  

Answer
Hi Keith, Inside the radiator is a tank that the trans fluid runs in. If the tank should develop a hole then trans fluid will get into the coolant. You have 2 choices. 1) replace the rad and then flush and refill the cooling system. 2) Take the rad to a radiator shop and have them replace the transmission oil cooler if the rad is still ok and then flush and refill the cooling system. Bill