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Old 03-17-2019, 01:52 PM
oldskewel oldskewel is offline
Join Date: Nov 2014
Location: SF Bay Area
Posts: 911
oldskewel is on a distinguished road
Originally Posted by Russianblue View Post
...iím not looking to skimp on fluid quality but not unlike motor oil grades, Dex VI is Dex VI... and then itís just opinions and experience after that.
I agree. But that Valvoline stuff is not Dex VI. BTW, I use that stuff in my Honda's, which specify Honda DW-1, and this stuff is widely reported to work at least as well as that. So it's not like I have anything against it.

But that Castrol Transmax DEXRON VI really is Dex VI. It says so right on the label, and if it were not Dex VI, they would not be allowed to say it. "Being Dex VI" means it meets the specs set by GM, which is the owner of the specification/brand.

The Valvoline, not being Dex VI, can't legally say that it is. They feel confident that cars that specify Dex III or Dex VI can use it safely, so they say the much weaker "Recommended for DEX/MERC* ..." If this stuff actually met the specs for Dex VI, was tested and certified as such by GM, then they would say DEXRON VI. But they did not (and probably can not), so they can't. Not saying at all that it's bad stuff, just that it is not exactly Dex VI.

My Honda AT's aren't GM, and they are not known for being good at all, in fact they are typically the weakest part on the whole vehicle. So in a case like that, I'm willing to stray beyond the spec.

But these AT's for the 3.0i's were made by GM Hydramatic in Strasbourg, France. And GM owns the DEXRON specs. So it makes sense that those ATs were designed carefully to work with the Dex III spec. And then when VI superseded III, claiming backward compatibility, it is not so clear, but I decided to go with the VI. Basically, since it is a GM AT, and is known to be a good one, I put more faith in what BMW / GM say and follow more exactly.

And that Castrol Dex VI is exactly what I used when I did my AT D+F's shortly after getting my 3.0i at about 168k miles. That was the first time ever on this AT at that mileage. Still working great, now at 188k miles.
2001 X5 3.0i, 190k miles, AT, owned since 2014
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