Valvoline Type F ATF for Ford C4/C6/FMX, Case of 6

Type F is the fluid the old Ford automatics were designed to run on, and it is not interchangeable with the Mercon and Dexron fluids that came later. What makes it different is that it is non-friction-modified. Modern ATFs add friction modifiers so clutches engage soft and quiet; Type F leaves them out, so the clutches and bands grab with high static friction. In a C4, C6, or FMX that means the firm, positive shifts those units were built around instead of the slurred, slipping engagement you get if someone fills them with the wrong fluid.

This is genuine Valvoline Type F meeting Ford specification M2C33-F (and the earlier M2C3-G). It is recommended for all Ford passenger-car automatic transmissions built prior to 1977, and many 1977 through 1980 models, which covers the C4, C6, FMX and Cruise-O-Matic families you find behind small blocks, FE motors and 300 sixes. It is also approved for a number of older Mazda, Toyota, Saab, Volvo and other import automatics that call out a Type F fluid on the dipstick, so check your spec before you fill.

Builders reach for Type F on purpose too. Drop it into a TH400 or a B&M-kitted unit and the higher friction firms up the 1-2 and 2-3 shifts without any valve-body work, which is why it shows up in a lot of hot-rod and towing builds. Just do not put it in a transmission that calls for Mercon or Dexron VI as a shortcut, because the missing friction modifiers will make a modern unit shift harsh and chatter the converter clutch.

This is a case of six one-quart bottles, 32 fluid ounces each. A dry C6 takes right around 12 quarts to fill through the converter, and a drain-and-fill on a C4 is a few quarts, so a six pack covers a service with some left on the shelf. Run it in through the dipstick tube or a cooler-line exchange and set the level hot, in gear, on level ground.