mixing new fluid with old?

[thegoose]

I plan to do an atx oil change on our '94 ford taurus (77,000 klms)in the near future and was wondering about using synthetic atf knowing that there is still fluid (original factory) left in the tc. Will they readily mix? Any thing I should worry about?

 

[MONKEYMAN]

Maybe the experts can give you a definative answer. Personal experience is that I have a 99 SL2 Saturn. I have drained and refilled Castrol Dexron III and replaced with Mobil 1 Dexron III two times, so now it is mostly Mobil 1. Only difference I could tell is it shifted smoother/worked better. No negatives noticed.

 

[unDummy]

They mix and there is nothing to worry about.