Originally Posted By: hardheaded
any real world testing on these fluids ?
You keep asking that but the truth is there is hardly ever any such thing as "real world testing", at least if I understand it the way I think you mean. Such a thing requires a statistically valid sample number and this is hard to achieve outside of a laboratory. Some large fleet operators such as taxi operations can sometimes use data from teardowns, but even then without identical engines driven in identical circumstances and conditions, conclusions are difficult. As far as I have ever seen here on BITOG no one does that - especially for some kind of valid comparison between M1 ATF and their Dexron VI product. All you are ever going to get here are testimonials and some very limited data usually expressed without any error bars.
As for "real world testing" that isn't statistically valid, you've gotten some here in this thread already. I told you I have gotten over 350,000 miles on my Sienna's A540E transmission using mostly M1 ATF over its lifetime. That's of limited value of course, since you have a different transmission being used in a different car, being driven in different conditions by a different driver. I also told you that I use Dexron VI in my 22-year old BMW which originally specified Dexron III. My opinion is that if an ancient BMW like that one can use Dexron VI successfully then anything can. But here again, that is my opinion based on my experience. Others have given you their opinions as well.
The only "real world testing" you have is what is done in the laboratory. For these choices you have Dexron VI that officially supersedes the former Dexron III product. That's official. So if you want any sort of "real world testing" to apply at all then this is it. Dexron VI is the fluid that is specified for your car, assuming it specified Dexron III (or earlier) in the first place.
With the M1 ATF you have the fact that ExxonMobil states on their website that it meets the MERCON V specification and:
Quote:
According to ExxonMobil, Mobil 1 Synthetic ATF is of the following quality level:
General Motors DEXRON® IIIH
On this one though, you're going to have to on the word of ExxonMobil and that's partly due to the fact that the Dexron III specification no longer exists. As a result the manufacturer cannot state it meets the specification since there isn't one. A judgement call is required on this one.
It has been my experience that when two choices seem nearly equally valid then it probably doesn't matter which one you choose and both will work. In this case I'll stick my neck out and say that will be your experience as well.