I have a 2003 Dodge Neon SXT. The transmission cooler in the radiator went bad and leaked all of the transmission fluid into the antifreeze. We replaced the radiator, flushed the transmission, replaced the transmission filter, and filled both the radiator and transmission with new fluid. (We used ATX+4 for both the flushing and filling and ATP transmission flush/conditioner)

Now when I slow down and the car downshifts around 25 MPH it shifts hard and jerks the car. I read about reseting the computer so I disconnected the battery for 10 minutes and tried it, but it's still doing it.

 

How long was the car driven with the mixed fluids in the transmission?

 

I can't say for certain. I know I had an oil change a week ago and they said all the fluids were good. Weds on the way home from work the transmission began to slip and when I checked it, it was empty (all in the coolant overflow)

There was very little water in the transmission pan when we took it off initially. Only a small amount of milky fluid in one corner of the pan.

 

It may be the solenoid pack; it may not be. The thing is, once those two fluids mix, the antifreeze eats the clutch material and essentially destroys the transmission. So, as it gets driven more and more with the "cocktail of death," it ruins the transmission more and more.

 

Yeah usually in that case I would just start looking for a new trans unless you can rebuild it yourself.