Trans fluid is a mystery that will never be solved in my opinion. Different friction material require different transmission fluids, but why is the question. Honda requires honda a.t.f, which I understand because it's one of the best fluids on the market and aftermarket frictions and factory work ideal with it, now other people don't agree with that statement, so who really is right? What I recomend is pull your trans dip stick and if it says mercon v or dexron vi or whatever put that back in there unless you just had a rebuild, then listen to the rebuild shop, because fluid is critical to friction material and computer calibration, also don't believe any transmission or dealership on which fluid you need, because there is a complex science involved in what fluid goes with each friction material and computer strategy. To tell you the truth... I can't give you a reason why the so called fluid the manufactuere calls for is needed, but until I do I'd go by it.
