Recommendations for trans fluid??
WoW, this got out of hand. What I want to Know is; when a auto trans is built today, with replacement parts made last week, is the materiels used to make the disks 50 year old formulas or new friction formulas?
@Scody21 I'm thinking a lot like you, chemical & friction properties have changed significantly over the years, and I also am looking for the best fluid for my transmission overhaul investment. All ATF+4 and Dexron-3 and higher numerically (current is 6) are all synthetics. These will hold up much better to higher temperatures than I conventional fluids will ever. They also run significantly cleaner. The major difference (in selection) is how one shifts over the other, it's a seat of the pants type of feel, and as you can see, everyone has an opinion - which is cool. As for my opinion, for what it's worth, I'm going with ATF+4. Price wise, as long as it says it is compatible with ATF+4 or "Dex" you're generally good-to-go. A manufacturer can't put the word "Dexron" on the label without paying GM a royalty and having GM test the fluid, which is why you see Dex instead of Dexron.
A friend of mine is a chemical engineer, there's no way he would put dollar-store oils in his engine or transmission. Buy brand-name product of Dexron 3-6 (III-VI) or ATF+4 or equivalent, at a good price, and call it a day.
BTW, I'm running a 904 with HD frictions & steels, an aluminum servo, a TransGo TF1 kit, and a 2800 stall converter (Edge Racing Converters) behind a long-rod 225 (225 HP). Power cruiser, not a racer. ATF+4.
