I'm about to be running my first auto, a late 60's ( I think ) C6.
It is built with an ATS converter and a manul valve body. What is the correct fluid to run in it? Type F or Dexron III/Mercon. From what I've heard the Dexron III will slip a little more than the type F but it doesn't really matter which one I run right???

Ask the builder. Its the clutches that dictate which fluid you need to run. I would imagine however, you can get away with runnng either, as long as you never switch to the other kind, or mix them.

I bought it from a guy who couldn't finish the project and was selling all his parts. All I know is a tranny guy at ATS turbo in Denver built it and not longer works there and I bought it months ago and don't even have the guy's # I bought it from.
I think I'll go with Dexron III and forget about it. If it does slip more that will be a good thing causes I'm not sure if I'll be able to stop the damn thing yet. Manual brakes+5.0 atlas+C6=no easy stoppie :confused:

I always heard from the Ford guys run type F........

Just run type F in it, you'll be fine,

i run type f

i run mercron dexon III my uncles rebuilds them for a living and that what he tells me to run

run type 3

type F

Run type F.

There are people out there experimenting with and recommending oils other than transmission fluid as well, but they generally are doing so in race type applications. I can't recommend using it at this time until I have done some testing on it myself to see what kind of durability the clutches will have in daily driving and towing situations.

a friend of mine ran synthetic straight 30 weight per tranny builders recommendations in a c-6 behind BBF 1600HP and it never held toge.ther .

With new clutches Type F is no longer needed.
Run normal shit.

For my automotive “Material and Processes class” I had back in 1994, we learned that type F fluid had less friction modifiers than the Dexron fluid. We also learned that type F was also comparable to (but not the same) B&M trick shift fluid. Bottom line lesson from the class, less friction modifiers, less slippage. Also during my automotive transmission class, we learned that running a fluid with less friction modifiers will keep your friction disks from wearing down for a longer period of time.

Since then, I’ve rebuilt Chevy and Ford automatic transmissions, and have used type F in both kinds. The only difference would be the newer transmissions with electronic valve bodies. For them, I run the Ford fluid designed for electronic valve bodies (not just type F).

a friend of mine ran synthetic straight 30 weight per tranny builders recommendations in a c-6 behind BBF 1600HP and it never held toge.ther .

Well I've run in similar circumstances, with similar results with type F, so I think you may not want to blame the oil yet, :D

i'd definetly run type f.

For my automotive “Material and Processes class” I had back in 1994, we learned that type F fluid had less friction modifiers than the Dexron fluid. We also learned that type F was also comparable to (but not the same) B&M trick shift fluid. Bottom line lesson from the class, less friction modifiers, less slippage. Also during my automotive transmission class, we learned that running a fluid with less friction modifiers will keep your friction disks from wearing down for a longer period of time.

Since then, I’ve rebuilt Chevy and Ford automatic transmissions, and have used type F in both kinds. The only difference would be the newer transmissions with electronic valve bodies. For them, I run the Ford fluid designed for electronic valve bodies (not just type F).


You are about the fifth different source of information that claims that type F fluid is comparable to Trick Shift. I have no reason to doubt the other people who claim this as they are good, accurate sources of information as well. This is the primary reason that I have stuck with running type F fluid in all non electronic transmissions.

I have used whatever fluid type is recommended by the manufacturer in the newer electronic transmissions so far, but haven't experimented with anything else yet.

Here are a couple of threads regarding motor oil and tractor oil being used as transmission fluid as well. My only concern is that it seems as though there have been very few cases where people put this kind of stuff in a "street" transmission or one that is expected to live a reasonably long life without being torn down. But then again, even if you have to rebuild a transmission once a wheeling season you're probably only out $100 or so.

http://www.fordmuscle.com/forums/c4-transmissions/motoroil-in-trans-is-it-good_56856.html

http://www.turbomustangs.com/smf/index.php?topic=58907.0

They are an interesting read if nothing else.

I used a B&M rebuild kit for my C6 and it specifically said in the instructions to use type F so that's what I run.

so I have a stock C6 from a bronco - not positive on the year.

Type F? I have some dex III on my shelf already, don't use it?

EDIT:

hmm looks like merc V? So how do you fill these guys, a few quarts before you fire it up and then check while running?

http://www.supermotors.net/getfile/499493/original/transfluid.gif

the guy who rebuilt my tranny told me to run type F because he used the old style clutches and the dextron eats the clutches

I finally pulled the dipstick, says CF or something which is replaced with mercon or whatever. Who woulda though.. pull the dip stick :p

I filled her up and it all came out of a few holes I had in my oil pan, oops :p