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Right, to clarify, I'm not referring to the newest of the new DEXRONŽ VI, MERCONŽ LV, SP low viscosity ATFs; don't run those in your 727.




WRT the Dex VI we'll have to agree to disagree on that one. Your competitors who make Dex VI specifically state it is backward compatible to Dex II and Dex III.

As far as I can tell, the differences in the ATF's friction modifiers are going to effect the way the clutch packs and bands grab. We're talking about what is happening for that brief moment while the clutch is slipping. That timing is critical in an automatic. However, as someone pointed out, it s hardly the only factor. Anyone who has modified their 727 ought to use the fluid characteristics their clutch supplier and/or builder recommends. Anyway, its the friction modifiers that result in Dex VI working fine for a plain ole 727 and ATF+ not working so well.

One advantage the Dex III had over II, and all the newer ATFs have over Dex III is the lower, low viscosity. An analogy to motor oil is that its like having a 10w-40 synthetic instead of a 20w-40 conventional oil. It means that even below operating temperature, the ATF acts more closely to the characterists it has when at operating temperature. For some applications, that's almost irrelevent, others its very important. For short drives and autocross, its important. If you're pulling to the line and loading the torque coverter, the fluid will be at operating temp real quick if it wasn't already.