[Alan Roehrich]

A quick and dirty explanation for the difference in the two fluids is that Type F replaced the older fluids for Ford, back when Ford still used asbestos in their friction materials, while GM got away from asbestos earlier, switching to paper friction materials, and Dexron. The different friction materials required different friction modifiers in the fluid, in order to achieve a certain shift feel.

The Type F fluid usually yields a firmer shift feel, when used with friction materials that do not contain asbestos, than Dexron does.

For years, race transmission companies recommended Type F to get that firm shift feel.

The old Type A, Type F, and early Dexron fluids were required by law to be compatible, even to the point of mixing them.

Some of the newer transmissions, like some of the Chrysler and Honda units, do require very special fluids, and do not work well with Type F, Dexron/Mercon, or other fluids. They can even be severely damaged by them.

The requirement of some companies to use a RED transmission fluids comes from the problems associated with the old blue B&M "Trick Shift" fluid (we used to leave out the "f") years ago. We found that the sealing rings and bushings often reacted negatively to the B&M fluid, and even noticed a higher incidence of problems with the Torrington thrust bearings.

I've found no difference in reliability or longevity with good quality Dexron or Type F fluids. Depending on what friction materials are used, you may or may not see a difference in shift feel.