04 neon trans fluid in antifreeze

With a 100 k on the odometer, the wife reports that the car started shaking, trans was slipping and check engine light came on after driving about two miles. She drives it at low speed back to the house. Investigation under the hood shows trans fluid in the radiator and coming out of the overflow tank. Engine starts right up and we have not had any other driveline problems since owning the car in 2005.
What is going on?

Transmission cooler leaking into the radiator. Check the transmission fluid as it probably has coolant in it.