Here's a post from FABO. Dexron III would be my choice.
Technical differences between F and the others is friction modifiers.
All of the Dex/Merc and related ATFs are friction modified. The modified ATF's change the way the clutches and bands grab and hold. All things being equal, the clutches and bands will grab quicker and harder with an unmodified ATF than a modified ATF. (They also may effect the release)
Type F. It's in a category of its own.
The only unmodified ATF with a dynamic coefficient that increases as clutches and bands lock up - resulting in firmer shifts.
If that's what you need, great. Drawback is that the fluid doesn't hold up as long. Result is often what @Duster346 has observed.
Dexron and Mercon - a chronology.
Gleanings from the web which appear to be more substantial than wild rumors, but you've been warned.
Dexron II 1973 - 1987
Dexron IIe was for electronic controls & had extra cleaning agents.
Mercon 1992- Contained less wax than Dexron
Dexron III c.1993 - Similar to Mercon. Lower low temperature viscosity than earlier versions of Dexron. Said to have better oxidation resistance and improved seal life.
ATF+3, ATF+4. Similar to Dexron but formulated specifically for
Chrysler transmission control modules. All of the manufacturer spec
sheets I found on-line seemed to agree - NOT recommended for DEX 3
applications.
Dexron VI. This was GM's latest standard (c 2008). By definition, Dex VI is fully synthetic and has the lowest low temperature viscosity. That
could be great for street and the first autocross run of the day. Several manufacturers specifically list it as backward compatible to Dex III and Dex II. I've used one of them. It's expensive, and if you have lingering doubts about using it, that cynicism seems reasonable to me.
I've used Dex II and III, Type F, ATF+, Dex VI at one time or another in my own 727 and 904s. The only one that I was really unhappy with how it seemed to effect the shifting was a ATF+3/+4.
edit: The current wikipedia page on Dexron seems very thorough. DEXRON - Wikipedia
and according to the following thread, is maintained by a Weber State prof John Kelly.
https://bobistheoilguy.com/forums/threads/modern-replacement-for-type-a-atf.311678/
Last edited: Aug 26, 2023
Technical differences between F and the others is friction modifiers.
All of the Dex/Merc and related ATFs are friction modified. The modified ATF's change the way the clutches and bands grab and hold. All things being equal, the clutches and bands will grab quicker and harder with an unmodified ATF than a modified ATF. (They also may effect the release)
Type F. It's in a category of its own.
The only unmodified ATF with a dynamic coefficient that increases as clutches and bands lock up - resulting in firmer shifts.
If that's what you need, great. Drawback is that the fluid doesn't hold up as long. Result is often what @Duster346 has observed.
Dexron and Mercon - a chronology.
Gleanings from the web which appear to be more substantial than wild rumors, but you've been warned.
Dexron II 1973 - 1987
Dexron IIe was for electronic controls & had extra cleaning agents.
Mercon 1992- Contained less wax than Dexron
Dexron III c.1993 - Similar to Mercon. Lower low temperature viscosity than earlier versions of Dexron. Said to have better oxidation resistance and improved seal life.
ATF+3, ATF+4. Similar to Dexron but formulated specifically for
Chrysler transmission control modules. All of the manufacturer spec
sheets I found on-line seemed to agree - NOT recommended for DEX 3
applications.
Dexron VI. This was GM's latest standard (c 2008). By definition, Dex VI is fully synthetic and has the lowest low temperature viscosity. That
could be great for street and the first autocross run of the day. Several manufacturers specifically list it as backward compatible to Dex III and Dex II. I've used one of them. It's expensive, and if you have lingering doubts about using it, that cynicism seems reasonable to me.
I've used Dex II and III, Type F, ATF+, Dex VI at one time or another in my own 727 and 904s. The only one that I was really unhappy with how it seemed to effect the shifting was a ATF+3/+4.
edit: The current wikipedia page on Dexron seems very thorough. DEXRON - Wikipedia
and according to the following thread, is maintained by a Weber State prof John Kelly.
https://bobistheoilguy.com/forums/threads/modern-replacement-for-type-a-atf.311678/
Last edited: Aug 26, 2023