C4 Transmission Fluid type

[Convert]

I am rebuilding my C4 and was wondering what fluid type should go in. Used to be Type F but now they have Mercon/Dexron III. It's a '79 vintage so was going to go with the Mercon but thought I would check with the experts.

Thanks....Keith B.

[jhannahokla]

i believe type f needs to go in there but im not 100% shure on that

[kknip]

Check out your dipstick for the trans,sometime it is stamped on the end.I think it should be type F.

[Clarko]

Type F from the start of Fordomatics through 1982. Mercon from 1983-up.

[hillbilly67]

Everybody is right. Type F. Careful of the new oils that state "For use in all transmissions" Fine for the new ones, but our old trucks need old oil! The reasoning behind this, is the additives that are in the oils, are not compatible with the clutch materials and glue that hold them on to the plates. There is a certain amount of acids and a LOT of detergents that are in the oils. Too much of one or not enough of the other raises hell with clutch material.

The exception to this is most rebuild kits these days use new kinds of materials that enable use of all-in-one oils. Better safe than sorry, though, as not all rebuild kit manufacturers do this.

[Clarko]

Type F is nice and thicker too.

[Convert]

Thanks for the info. I will go with good old Type F.