I'm about to change my tranny fluid and wondered what you guys are using. I see Mobil 1 makes a synthetic fluid that can be used in place of Mercon and Mercon V (and just about all the others).

 

I'm not a fan of dual rated fluids. The E4OD/4R100 cannot have friction modifiers in the fluid. Thats plain Mercon. The 4R70w needs friction modifiers. Thats Mercon V.

My truck gets the motorcraft Mercon in its 4R100, and if I had a 4R70w it would get the motorcraft Mercon V.

Adrianspeeder

 

I have heard good things about Royal Purple Synthetic liquids

 

I assume I have a 4R70s because my dipstick says use Mercon V. Also, I read about using the "dual" fluids in my owners manual if the truck has a 4R100