New Dexron VI ATF?

johnnyo4 · Feb 11, 2005

GM is going to start using a new rating of transmission fuid (Dexron VI). Anyone know anything about this fluid?
-------From GM site------------------------
During the first six months of 2005, GM Powertrain will transition from Dexron III Automatic Transmission Fluid to Dexron VI.

Dexron VI offers the longer-life characteristics in the table.

TIP: Dexron III and Dexron VI can be mixed with no problem.

Extended factory fill for life 150K miles for cars
200K miles for trucks
Clutch friction stability Improved 100%
Clutch durability due to fluid Improved 120%
Oil film thickness Increased 20%
Fluid oxidation Improved 100%
Foam / aeration Improved 150%
Shear stability Improved 200%

JHZR2 · Feb 11, 2005

Interesting. I think Ill use this for the next PM on my 98 chevy. With all those increased characteristics, I have to wonder how this stuff will do in PS systems designed for dex.

JMH

MolaKule · Feb 12, 2005

The info I have from all the Lube trade rags is that DexronIII(H) is the latest fluid specification. Can't see why they would go from Dexron III(H) to Dexron VI while skipping Dexron IV and V. I can see maybe skipping Dexron V so as not to confuse it with MerconV.

None of the add suplliers have said anything about a Dexron VI spec (yet)!

Addendum: Some of the additive suppliers have stated that future ATF fluids would have lower viscosites of 4.5 to 6 cSt viscosites verses today's fluid viscosities that average 7.0 cSt@100 C, probably for same reason as going to 5W20's in engine oils.

theguru · Feb 12, 2005

GM was going to Dexron 111(H) in all their new cars. Can't see that being superceded by a newer spec so soon. Maybe there is some confusion as to the new spec. The type H has been available here Sept 2003.

T-Keith · Feb 12, 2005

I couldn't find anything about it on GM's site. I agree it wouldn't make much sense to jump from 3 to 6. But, GM has several new transmissions coming out soon. The 6L80e a 6-speed high-HP RWD transmission, a FWD 6-speed that's quite unique for a GM transmission, and the new dual mode hybrid transmissions. Perhaps one of these dictated a new fluid.

-T

medic · Feb 12, 2005

Looks like it may be Dexron IV. Redline has already claimed that their Synthetic D4 ATF will meet the new Dexron IV spec.

I've also heard a rumor that Ford was working on a Mercon VI. Once again, going from 1,3,5 and then to 6 doesn't make much sense.

MolaKule · Feb 13, 2005

johnny04,

Please give the link to where you found the statement.

Thanks,

Mola

johnnyo4 · Feb 15, 2005

quote:

Originally posted by MolaKule:
johnny04,

Please give the link to where you found the statement.

Thanks,

Mola

Here's the link:
http://www.gmtechlink.com/images/issues/cnt_mo/TLcme.html#story5

ChrisW · Feb 15, 2005

would this VI stuff be applicable to anything that calls for a dexron III? Is III-H backwards compatible to regular chevron III?

reason i ask is because my bro's 94 honda civic uses dexron IIe, but responds very well to chevron dexron III. I ahve not tried honda fluid in it yet. Also, the toyota previa in the familt uses dexron.

nascarnation · Feb 15, 2005

It's definitely Dexron VI (as in 6)
Dex IV (as in 4) was nixed many years ago for cost during the development phase.
V was skipped to avoid confusion with Mercon.
It will be in pretty much everything GMNA starting in 06 model year, except Allison commercial which will still use the Castrol TranSynd.

theguru · Feb 16, 2005

quote:

Originally posted by ChrisW:
would this VI stuff be applicable to anything that calls for a dexron III? Is III-H backwards compatible to regular chevron III?

Dexron III-H is backward compatible with Dexron III.

MolaKule · Feb 16, 2005

Makes we wonder if Dexron VI isn't really Dexron III(H).

None of our additive suppliers have sent any bulletins on any new addpacks, other than Dexron III(H).

JohnBrowning · Feb 20, 2005

Molakule, Could it be a base stock switch? I ask because when I was working for GM I read a memo and an SAE studie they performed useing an custom blended ester ATF. It grossly outperformed anything currently being used by them. They did extensive testing in AZ testing center and used a towing dyno and a full size truck. THey used Dex III as the reference oil in the testing.

I am working from memory so do not quote me!

MolaKule · Feb 21, 2005

For automatic transmission fluids, the Level of Specification, whether it be a DexronIII(H), a Mercon variety, Toyota T-IV, Honda ATF-Z1, or whathaveyou, DOES NOT specifiy the base oils.

The fluid developer must come up witha fluid that meets the specification for oxidation resistance, friction modification retention, etc.

Ususally, an additive company like Afton (formerly Ethyl) or Lubrizol, or Infineum, or XYZ, comes up with an add pack for that specification. They then suggest a base oil mix for that formulation.

The formulation gets tested, and if it passes, everything is hunky dory. Usually, it doesn't pass the first time and has to be tweaked for various reasons, such as for example, friction modification retention.

After testing, the additive supplier is confident the additive package can meet the specification requirements for various base fluids.

As the specification heat is turned up, higher Group fluids must be used, such as Group III minimum, in order to pass certain tests.

TomJones76 · Feb 21, 2005

While it seems silly for GM to skip two revision levels of Dexron, there is some precedent in other fields. Maybe 5 years ago, a Linux OS distribution organization named Slackware went straight from a version 2 to a version 7. The reason? The Redhat Corporation, one of their competitors, was on version 6, about to release 7, and Slackware didn't want to be perceived as backwards.

New Dexron VI ATF?

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