Ford Repair: transmission fluid leak, radiator hose, ford taurus

Question
3 weeks ago I noticed that the coolant in the reservoir of my 2000 Ford Taurus with 155k miles was brown and looked muddy with an oil like smell. My research led me to think that there is a leak in the transmission lines inside the radiator and ATF was leaking into the radiator. I took the car to the repair shop to have the radiator and the reservoir replaced. The mechanic discovered that the hose leading from the coolant reservoir to the radiator was clogged and told me that the radiator was ok and only the hose and reservoir should be replaced, which he did along with a cooling system flush and adding 2 gallons of coolant.
A few days later I realized that this didn't fix the problem and I was sure that ATF was leaking from the lines inside the radiator and that I needed a new radiator. Then the transmission started slipping and when I checked the ATF level the fluid is also brown and looked muddy.
When I began to loosen the lower radiator hose to drain the coolant expecting it to look muddy, to my surprise the coolant in the radiator looks normal. What's puzzling to me is why there’s a fluid/coolant mix in the transmission and reservoir and not in the radiator. Also, should I take the car to my mechanic or to a transmission shop for repair?


Answer
Hey there. Im sorry to here that you are having so many trouble. YES this definitly indicates a leak internaly inside the radiator. It may be minor but any leak there is not a good leak. the oil will only be in the resevoir because any oil always floats on top of water! the oil will find the highest spot to rest. IN this case your collant degaser bottle. I would replace the rad, reflush the cooling system, do a complete flush on the transmsion and pray to god no other damage was done. let me know what happens. good luck
Chris P