the confusing world of transmission Fluid

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72HCODE

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In my continuing research of the C6 I came across the debate between Type F versus Dexron III/Mercon, Mercon versus Mercon V.

There are some pitfalls in this but no absolute wrong anwsers.

the Deal with Type F: Type F was spec'ed for use in 1968-1975 C6 transmissions. in 1976 Ford changed from Type F to Dexron. Mercon became the replacement for Dexron sometime in the 1990s.

Currently Mercon V is the ford standard.

What does all this mean?

before 1976 the clutch bands Ford used were made of Asbestos. After 1976 they went to a safer Organic clutch material. this change from asbestos to organic required a friction modifier.

Type F fluid was basically the first and had no friction modifiers. People say it Grips harder for the clutches and yes it does, people swear Type F makes for much firmer shifts, at the cost of clutch pack wear.

Dexron is always tied with a softer shifting transmission. however this could also be because ford shifted production to softer shifting transmissions and got rid of the Clunk people complained about which was the bands gripping firmer.

now Dexron/Mercon and Type F are not compatible so you do not want to mix them inside a transmission. in order to change fluids you must flush a transmission completely. The bottle of Dexron and Mercon say do not use in transmissions that require Type F fluid and this is true unless the transmission has been completely rebuilt, this equates to the transmission being completely flushed. At that point you can use Dexron or mercon in the transmission. the whole point is the clutches and the material they are made out of. you cannot get asbestos clutch bands since at least the early 1980s so everything is organic now.

so as one ford tech stated:

If you have a new rebuilt transmission use Mercon V, if not use Type F.

Chances are somebody used Type F to fill it up since the manual stated to use Type F so unless you know for sure stick with Type F, otherwise use Mercon V

it gets more confusing since people have used all 3 different fluids for years and have reported no problems. most transmission techs have said they have never seen a failure caused by the fluid there is always a mechanical failure involved.

So what can we take from this:

well more confusion since you have the performance crowd that sticks with Type F because they feel it slips less, even though they have organic clutches and not asbestos.

Then you have the ford techs that just say use the newest standard which is mercon V.

Then you have the Transmission techs that are all over the place, and it comes down to use whatever fluid the transmission place tells you so you do not void the warranty.

then you have the really techy guys that say "Once you start dealing with transmissions that use fiber lined syncros, the differences in friction modifiers may become more apparent."

So i leave it up to you to decide because there isn't really a right answer;

Other then DO NOT mix different fluids inside a transmission.

food for thought

 
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Thanks for the info, I think...

Seems like something so simple as what trans fluid to use really isn't as you suggest. Out of all this I have a question as it relates to my build. I have a recently rebuilt 73 C6 that I filled with type F. I am going to leave it as I hate draining the fluid and trying to get the pan to seal. Does someone make a friction modifier that I could add to the type F so all would be good?

Something else related to this is all types of radiator anti freeze are not created equal and should not be used in our cars...

 

72HCODE

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at this point, Leave it be! that is the one thing i learned at this point stick with type F and just drive it. if you do have issues down the road then most likely it wasn't the fluid.

from what i have read there is no additive for transmission fluids.

one debate was if you get more clutch wear from the type F then what? and everyone was like just change the fluid every 12,000miles.

i think this becomes more an issue for a daily driver where you expect to put over 15,000 miles a year on it with constant oil changes.

My choice is i'm going to use Mercon V during my build and then fill with mercon V and see what happens.

my last trans was rebuilt, i used type F and while i have mechanical damage in that trans i did see lots of clutch material in the fluid, so i want to try the mercon V and just see what happens since i have total control over this new rebuild i'm doing.

radiator coolant basically turns bad after a couple of years, most of us do not drive much so it is a good idea to flush it every few years and keep it fresh.

 
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Kit Sullivan

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Mixing Type-F with dex/merc will not hurt a healthy transmission that originally called for Type-F. Using Type-F or mixing it with dex/merc in a trans calling for d/m or MV may cause slight accelerated wear, but probably no driveability issues.

 

MeZapU

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FWIW

When I purchased a new C6 for my car back in 1997 from Art Carr transmissions, it came with all the installation instructions except which type of fluid to run in it. Since I ordered it with the upgraded clutches I too wondered if it used the more modern fluids or not. I called them up, and as soon as I asked the question the tech replied with, "Type F only". I ran it and never had a single issue. So when in doubt, use the recommended fluid from the shop that will honor the warranty if something goes wrong.

 

72HCODE

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I put in a phone call to raybestos that manufactured the clutches for my master rebuild kit. The operator told me they would get back to me, let's see if they do.

 
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Great article! But as mentioned, adds to the confusion of what to use.

A couple of related questions: I believe there is a synthetic Type F so how would this play into the picture, Type F synthetic vs non synthetic? Also would power steering still use Type F or is that also as confusing?

Thanks

 

72HCODE

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update:

I contacted 'raybestos' they manufacturer the clutches for Scott Drake's C6 master rebuild kit and heard back from them;

so get this "They have no idea either" the first guy i spoke to said he didn't know and would try to bump it up the food chain for an answer.

the plot thickens.

I've not heard any issues with synthetic Type F verse non-synthetic Type F. The racing guys seem to go with synthetic as it has a higher temp rating usually. it is suppose to be safe to mix them as well.

for the power steering system Stick with Type F it was designed for it and usually original pumps are in good shape and you want to keep using type F in them, do not use power steering fluid in them as it expands differently from the type F transmission fluid.

 

72HCODE

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updated again:

so raybestos contacted me again with basically a non-answer

"When we manufacture a replacement friction plate, we use materials that are compatible with fluid the OE manufacturer recommends to use."

Except the whole point is there is no way they are using Asbestos in these clutch bands(i asked and got no answer).

the whole point of Type F was dealing with Asbestos clutch bands.

so here is the kicker they use the same clutch bands in 68-90 rebuild kits, so are they specing type 'F' for 1968-1975 transmissions and mercon for 1976 to 1992 transmissions with the same bands in either kit?

then it doesn't seem to matter which fluid you use and either is correct.

I guess I'll just change my stance on using mercon V and buy Type 'F' and be done with it.

you would think you could get a 100% answer from the manufacturer but they don't even know LOL

(since they also make GM bands out of the same material then i guess you could use anything in the transmissions)

 

barnett468

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the type f is not for asbestos bands or plates . . other companies used asbestos bands also but ran different fluid than ford did.

if a newly rebuilt trans chatters when shifting with type F, using oil with friction modifiers may reduce the prob . . if it does not, the plates are crap and/or the trans was improperly built.

some of the clutch plates and bands available are total crap . . raybestos sells a lower priced crap line and a good line . . borg warner are good for stock street builds, red altos with kolene steel discs are the ones for high perf builds and always has been . . kevlar bands should never be used on a street trans.

 
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