I have an 1989 F-150 300 I with C6 auto 3 spd, I am looking to change the fluid. However, I have been getting mixed advice on the fluid. You see, I don't have the manual. The dipstick has Mercron on it, but I have reason to believe that it may not be the factory original dipstick. When I have asked around here I have been told Dextron I, Dextron II and even Dextron III/Mercron! Does anyone know for sure? Either by the manual or what you use in your C6 of about the same year. Or where I can go to find out for sure? Any and all advice welcome. Thanks for your time,
Lance

 

Mercon, NOT Mercon V

 

Mercon OR Dextron III is good-If in doubt Call the NEAREST ford dealer-They will
tell you for sure. But the C-6 Auto is so tough you could put rocks in it-IT WOULD
STILL RUN! they are 1 tough tranny