Is Dexron VI fully backwards compatable?

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I have several GM vehicles in which Dexron III (or even Dexron II), was factory fill. I am concerned about the quality of the "Multi-Vehicle" Fluids that have sprung up with the cancellation of licensing of Dexron III. However, I also don't want to cause damage to my transmissions because of using incompatable fluid. What do you guys think?

Thanks, Dave
 
Gm has stated in numerous articles that Dexron VI is the replacement for Dexron III and earlier Dexron fluids.

The reason some people are afraid to use it is because the initial viscosity is lower than Dexron III. However, Dexron III shears more than Dexron VI.

Buy some Dexron VI, and use it.
 
Can you just add Dexron VI to a transmission which has mostly Dexron III in it, or should you replace the Dexron III completely with Dexron VI?

Dave
 
What about non-GM applications?

I have a 1988 Mercedes 420SEL that calls for Dex II in the tranny. I've been using Dex III, and I'm contemplating a switch to Dex VI, but I'm not entirely convinced it's the right thing to do.
 
http://www.imakenews.com/lng/e_article000801715.cfm?x=b11,0,w

Quote:
GM introduced the trademarked Dexron-VI automatic transmission fluid in April 2005, calling it a significant upgrade over the previous spec, Dexron-III(H). The company ceased issuing Dexron-III(H) licenses at the end of 2005, meaning all such licenses expired at the end of 2006 and would not be renewed.


Eventually you'll have switch because GM has stopped licensing Dexron III. Or you can buy a life time's worth of Dexron III now.
 
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I would presume that the newer products such as "DEX/MERC" and the like get around the non-license issue because they do NOT use the full product name of Dexron III or Mercon. That addresses the label wording and makes it legal to use, yet the product is still recognizable to most people, as it sits on the shelf.

As for the formulations? I would expect they are basically the same as they had been, before the licenses expired. Techinically, since there is no license to be obtained, then there is no current "authority" by GM/Ford to control the formerly-licensed products. Still - I expect that large companines such as Mobil, Valvoline, Pennzoil, Castrol, etc are interested in the balance of marketability, profitability, quality, and image; they are, in fact, always in this light. So I expect that there's been little if any effective change in the forumlations moving from Dexron III/Mercon licensed fluids to "DEX/MERC" non-licensed fluids.

I agree that the DEX VI product is a vastly improved one over III. However, if you use a DEX/Merc unlicensed fluid, you'll just have to stick to the old OCI, that's all; I expect that they will perform more than adequately.
 
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For GM vehicles I would use Dex VI and I do. I've used it in a 4L60E and soon will be using it in a 4T65E transmission. I did a flush on the 4L60E but it isn't necessary. However if you want the full advantages of the better fluid you need to flush out all the older Dex III fluid. Mixing causes no harm.

Some people have said that some of the Dex/Merc fluids have reverted to older spec. levels of the Dex III (g versus h for instance) since the license has expired. You have no way of knowing. However if you use a name brand fluid and keep your intervals short enough it is probably fine.
 
It really boils down to whether you want to run a GM approved ATF or not. It's like pouring in an non-API approved oil into your engine or not. There shouldn't be any problems but the ATF/oil isn't approved and is not routinely inspected by GM or API for compliance.
 
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Dexron-VI is certified backwards compatible only in GM's Hydramatic transmissions. It is not backwards compatible in Allison transmissions, and may not be in transmissions of other brands that originally called for Dex-III or Dex-II.

Licensed Dexron-III is still being made, only now the spec is called Allison TES-389.

I'd fully trust all the unlicensed Dexron products made by any major outfit...Chevron, Mobil, etc.
 
Originally Posted By: Ken2
Dexron-VI is certified backwards compatible only in GM's Hydramatic transmissions. It is not backwards compatible in Allison transmissions, and may not be in transmissions of other brands that originally called for Dex-III or Dex-II.

Licensed Dexron-III is still being made, only now the spec is called Allison TES-389.

I'd fully trust all the unlicensed Dexron products made by any major outfit...Chevron, Mobil, etc.


I would like to hear from someone that works for or has worked for one of the major outfits to see if they indeed really do continue to match the old spec.

In my world (I'm an ISO auditor and consultant) most nearly every time that a company claims to be compliant to ISO without being registered, they really are not. They need the discipline of 3rd party audits to stay on the straight and narrow.

I can't help but think it would be the same in this situation as well. Any comments welcome.
 
Originally Posted By: Cutehumor
is the shifting better when using dex 6 in a dex 3 spec auto transmission????


I did not notice any difference at all when I switched. Others have noticed some changes however. My old Dex III fluid I flushed out was still in pretty good shape however. The advantages of Dex VI are mostly longer life due to improved durability.
 
If DexronVI is not in the budget, another option is Mercon-V for those dex3/merc trannies.
There should be no issue with using a fluid blended to a previous spec, regardless of whether it has a license or not.
A license doesn't guarantee that corners aren't being cut either.
 
It is indeed an excellent choice. I ran Mercon V in several Toyota Dexron III transmissions and power steering systems and it performed flawlessly.
 
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