dexron III instead of dexron VI..*gulp*

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parts guy at the dealer sold me 8 quarts of dexronIII said this is waht they use in the shop..after dumping the atf into the tranny and fireing it up, i noticed the dip stick says dexron VI on it...now what?

my truck is a 06 duramax with a 6 speed allison auto transmission...
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Go to the service department, show them the stick of dip, tell them what THEIR supposedly trained seller of parts said, then firmly ask them to do what they know needs done.

If step one doesn't work, come back here.
 
You need to get the correct fluid, Dex VI, flush all the Dex III out, and put the Dex VI in.

This transmission was not designed to operate correctly on Dex III.
 
Assuming it'll run fine on Dex III, keep in mind that the main difference between the two fluids is that the useful life of Dex III is half that of Dex VI.
 
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Actually your Allison will run fine on Dex III.




My mistake. I was thinking he had the new 6 speed that requires Dex VI. He needs to make sure he doesn't before continuing to use Dex III.

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Assuming it'll run fine on Dex III, keep in mind that the main difference between the two fluids is that the useful life of Dex III is half that of Dex VI.




Actually, the biggest difference between Dex III and Dex VI is the viscosity. Dex VI is a much thinner ATF.
 
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From older discussion, I was under the impression that Dex VI was only a little thinner, not much thinner.




Around 7.0 cap for Dex VI, if I remember correctly. I think Dex III is capped at around 8.5.
 
Its an Allison, use a TES-295 ATF.

If the vehicle isn't worked, the DexronIII will work fine. I just don't see it as a fluid for extended usage. Throw in a bottle of lubegard red, run it for 10k miles, then switch back to DexronVI or a full synthetic Dexron III.
 
Dex VI is capped in the mid 6 range, but the Petro-Canada Dex VI product is 6.0cst @ 100C. Most Dex IIIH fluids are 7.5.

While the fluid may be OK for the transmission in terms of protection, GM may have changed some programming of the transmission software to accommodate the Dex VI fluid. For instance, since Dex VI flows much better (and is much thinner) at low temps compared to Dex IIIH, the transmission may behave strangely if operated under extremely cold conditions.
 
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Dex VI is capped in the mid 6 range, but the Petro-Canada Dex VI product is 6.0cst @ 100C. Most Dex IIIH fluids are 7.5.




I've got just one thing to say to you:
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The DEXRON-VI fluid is thnner when it's new (6.0cSt at 100C as you said) however the DEXRON-III fluids are typically not shear stable so the viscosity drops rapidly from about 7.5 cSt at 100C when new to about 5.0 cst in just a few thousand miles. In the end they can go as low as 4.0 cst.
The viscosity difference is the most visible feature of DEXRON-VI vs DEXRON-III but it isn't the biggest difference. The biggest differences are in thermal stability and friction durability (compare the specs and you will see.
 
This is what it says on Wikipedia.



This says that the thinner Dexron VI is better than the min shear viscosity of 4.2. it also says that it maintains viscosity better Than Dexron 3.


As for Amsoil ATF specs



Even the Amsoil OEM version of their ATF thin is 5.8, still better than the min requirement of 4.2

Amsoil has warranty secure for their products. They stand behind it even when it's still under manufacturer warranty.

Believe it. I am not an Amsoil Dealer, but I have studied data and third party test about them. They appear to be as good as their claims. Also, Amsoil has longer life than most other brands.
 
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Amsoil's ATL is imply their LV version of the 6.X cSt ATF comparable to Dexron VI.

See

Dexron VI Improvements

and Whitewolf's quote above (he helped develop it):

Originally Posted By: Whitewolf
The DEXRON-VI fluid is thnner when it's new (6.0cSt at 100C as you said) however the DEXRON-III fluids are typically not shear stable so the viscosity drops rapidly from about 7.5 cSt at 100C when new to about 5.0 cst in just a few thousand miles. In the end they can go as low as 4.0 cst.
The viscosity difference is the most visible feature of DEXRON-VI vs DEXRON-III but it isn't the biggest difference. The biggest differences are in thermal stability and friction durability (compare the specs and you will see.
 
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So to beat a dead horse a bit more....

Can one assume that there will be no compromise in performance when using Dexron VI in 50 year old (rebuilt) Turbo 400 design, since the original Dex II quickly sheared to lower viscosity? Is this the best fluid choice for a TH400?
 
Originally Posted By: novadude
So to beat a dead horse a bit more....

Can one assume that there will be no compromise in performance when using Dexron VI in 50 year old (rebuilt) Turbo 400 design, since the original Dex II quickly sheared to lower viscosity? Is this the best fluid choice for a TH400?


A LOT of variables here! What's the application? Transmission build specific's?
 
Originally Posted By: novadude
So to beat a dead horse a bit more....
Can one assume that there will be no compromise in performance when using Dexron VI
in 50 year old (rebuilt) Turbo 400 design, since the original Dex II quickly sheared to lower viscosity? Is this the best fluid choice for a TH400?


Yes.

If this rebuilt unit was tuned for racing then Type "F" is the fluid to use.

Otherwise, DEXRON VI should work just fine since it is an improvement over the earlier Dexrons'.
 
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