Thread: Synthetic tranny fluid brands?

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Hope to get the c6 in this weekend. Any synthetic brand preferences for fluid? Also when to change fluid(newly rebuilt!). I went and got Castrol Mercon 5 yesterday, but haven't used it yet, so I figured I'd ask what is a good reasonably priced fluid. The Purple stuff is just too expensive at 13-15 dollars a quart for my budget unless it can work miracles!

I use the Mobile 1 synthetic in my c6, I'm also racing it. What are you going to do with the trans?

Just local cruising, occassional burnout or two, highway use on the weekend. Not a daily driver or a racer.

i use trick shift. with my old tranny i just add 1 quart per change with my regular tranny fluid.

Is it ok to use synthetic fliud in a new transmission, I know you are not suppose to in a new motor? Just asking, I do not know the answer, and would hate to see something go wrong. Now this is not a C6 but I just put a rebuilt 4l80 in my work van and the rebuilder said O'Rielly fluid was fine, change at 50,000 miles. Edd

I used amsoil in my 400 a highly modified reverse valve body from the start.

i have had some 400s trans over the 24years with alot of bling in them i allways used just ford F

In a Ford, and either a C4 or C6 I wouldn't deviate from F (or FA - a bit 'better" if you can find it). My choice has been Valvoline, but many other brands I'm sure are just as good. Syn in a transmission designed for a non-syn oil - not sure what the benefits are except to increase the profit line of the manufacturer. I've successfully used F and FA in every C4 or 6 from cars and trucks that are stock to pretty dang wild for many years.

The Castrol Mercon 5 is made for Ford transmissions. When I was a kid it was easy they made two kinds, Ford and everyone else. Now there are litterally hundreds of types, and the original fluids aren't even produced anymore. I talked with Sam the transmission Guy and he said synthetics will keep operating temps lower and extend the life of the transmission. He also said the aftermarket pan from derale would further keep things cool, so I'm not sure where to go with the fluid. Mobil 1 synthetic was also recogmended by him. He did say all the fluids are pretty much made at the same plant, and a lot of what you are buying is a name. I guess I was just looking to hear what you guys use. Probably will go with the syn 1 from Mobil.

i always use either valvoline or castrol type f int he racecar and normal gm stuff for the blazer. basically all trick shift is is type f

Originally Posted by stovens

The Castrol Mercon 5 is made for Ford transmissions.

Steve - Mercon is for the later Ford transmissions - as are many of the syns. I'd hate to hear that you 'dumped' an expensive transmission and torque converter - why not give someone like TCI, or ATI a call rather listen to our ramblings.

i am cheap i always used F i have $3000 + in just hard parts in one 400 maybe i should use some thing better? but it seam to work fine been doing it that from 1981 with the 400s

doesn't much matter in a auto trans as basicly its just a hydraulic fluid and they only want minimunal slippage so lube qualities(slipperyness) is secondary--we always used type f so the clutch discs bit better--you know the old better bite thing-

In our 500 hemi making 1380 hp with a torqueflite, there is aprox 1000 +- rpm slippage at 9000+rpm and we want to limit that as much as possible

Thanks guys! It is a mystery why there are so many different types out there. I went to Mobil 1's site are read a disclaimer that it is not for older Fords. Yet that is exactly what the transmission guy recogmended. He said with the synthetics it doesn't matter?
But he also is a nice guy, highly recommended by all the local shops! When I went to Napa Auto, they didn't sell the mobil one, so I picked up the Castrol Oil brand. It says on the bottle for type F transmissions. My tranny is out of a 71 lincoln, so it is an older model, yet it was just rebuilt within the last year.
After reading the above post, I read the fine print on the back of the Mercon 5 atf. It says certified use in all Ford That require Mercon or Mercon V, but lower down, not for use in applications calling for Mercon SP or type F.........................Yikes!
Dam fine print, fortunately I haven't put any fluid in anything yet! Thanks for the warning Dave!

O.K.
Got the 1100.00 dollar answer from Sam at the rebuild shop today. My transmission was rebuilt with new parts/materials since the old clutches were built out of asbestos, and because of this it is fine to use Mercon or a Synthetic. He recogmended Mobil 1 because thats what they use, and said it seems to extend the life of the transmission. Since he will warrent the tranny with this fluid, this is the way I'll go. Thank you all for advice and help. I guess it was worth waiting for the shop to open this morning. Sorry to post such a nervous nelly thread!