What is the best tranny fluid to run in an AOD? I know it says Mercon, but is there something better?

 

I saw a post somewhere where someone said merc 5 is a better choice. Is that just because it's synthetic?

 

Mercon V supersedes Mercon.

 

Ok. So is it worth it to pay more for merc 5 or is it just the new stuff?

 

Ford changed most of the specs to V...........as for the science and technical comparisons here's one place to research


The Petroleum Quality Institute of America


(Also just noticed your call sign --- I'm running a 351C in a 1966 "S" Fairlane GT which I've owned for over 25 years---incredible engine (air pump) and it lifts the front wheels on good days......11 second machine in the 1/4 mile without breathing very hard too)

 

Yea they are strong engines. The ford engineers back in the day had a damn good design going. Too bad they killed it off. But the Aussies picked it up and ran them all the way until '82.

 

The red kind....
There really isn't a trans fluid that's better than another really. There's plenty of tests that show each fluid in certain situations and which one performs better. Really type f and b&m trick shift perform nearly the same. Mercon V is "the new" ford fluid. It is compatible with all transmissions except ones currently using type f. If it was rebuilt with new seals, and for new fluid, then they can use merconV.
Choose a fluid that's compatible with the seals.
In an aod, I really doubt you'll notice a difference between the 3 and 5.

 

Ok. I just was wondering.

I went and picked up a case of dex/merc from sams club. At $2 a quart that's less than half price of the parts stores. We've been running it in our 99 super duty and it's been running fine. So it must be ok stuff.

 

I think 03+ requires merconV so your 99 is fine. My 02 and 00 superduty is also running merconIII just as good as well.
So SAMs club trans fluid should work fine.

 

Yea. I've been researching who makes it for sams, the only thing I've found is that it's made by shell. So that's good I guess.