Transynd instead of DEXVI?

[THE YETI]

So I come from the Duramax world.  I've always bought Transynd by the 5 gallon pail.  Is Transynd a recommended option for this new 2021 HD 6 speed gas trucks?

[newdude]

12 minutes ago, THE YETI said:

So I come from the Duramax world.  I've always bought Transynd by the 5 gallon pail.  Is Transynd a recommended option for this new 2021 HD 6 speed gas trucks?

 

 

No.  Dexron VI.  Transynd is a Dexron III fluid, will not work in a trans that calls for Dexron VI.  

Edited September 11, 2021 by newdude

[THE YETI]

10-4 buddy thanks.  Appreciate the answer.  But in my previous experience my Duramaxs called for DexVI (2006+ models) and Transynd was recommended for an upgraded fluid being that it is a TES-295 certified fluid and recommended by Allison.  That was why my thoughts led me to think it would be fine to use in the new truck.  You definately now have me second guessing my theory though.

[newdude]

34 minutes ago, THE YETI said:

10-4 buddy thanks.  Appreciate the answer.  But in my previous experience my Duramaxs called for DexVI (2006+ models) and Transynd was recommended for an upgraded fluid being that it is a TES-295 certified fluid and recommended by Allison.  That was why my thoughts led me to think it would be fine to use in the new truck.  You definately now have me second guessing my theory though.

 

 

Transynd in the Allisons was a good thing.  Allison called for TES-295 fluids which were synthetic Dexron III fluids.  GM from 2001-2005 was still using Dexron III.  When GM switched to Dexron VI, Allison wasn't exactly, pleased initially.  They still wanted a TES-295 fluid.  In the end, they had to re-design some of the seals to be Dexron VI compatible as it was a more "aggressive" fluid than Dexron III (not sure in what ways).  Allison still however called for TES-295 spec fluids for all Allison 1000s that were not GM applications.  Allison to this day still does not want Dexron VI in their products, even with the compatible seals.  

 

So Dexron III/Transynd are compatible but not Transynd and Dexron VI.

 

Here is 73 pages of awesomeness on Transynd started by a retired engineer from Allison.  

 

Former Allison Transmission Fluids Engineer (Mr. TranSynd) | Chevy and GMC Duramax Diesel Forum (duramaxforum.com)

Edited September 11, 2021 by newdude

[elcamino]

GM got the rights to build the Allison 1000 Series transmission in GM factories as part of the sale of Allison away from GM. Allison has no say in what atf to use as they DO NOT build the 1000 trans for GM vehicles, GM builds it.

Edited September 11, 2021 by elcamino

[THE YETI]

Read that thread years ago. Thanks for jarring my memory as to why I switched all those years ago newdude.

 

And yes elcamino I know that as well.  But the builds that were still to Allison specs the first couple after I would still be willing to use Allisons recomendations.  That along with the fact that Allison designed the transmissions they should know best IMHO.  But all said and done I guess I will avoid using the Transynd in the 21'.  Thanks for the replies guys.

Edited September 11, 2021 by THE YETI

[Grumpy Bear]

Seal issues are base oil compatibility issues. Natural rubbers do not like esters. But base oil is not part of the Dexos III or VI spec so.....???? 

 

The biggest difference between III and VI is viscosity. The friction package must be nearly the same as VI is backward compatible. 

 

 

That isn't confusing or anything.

[THE YETI]

55 minutes ago, Grumpy Bear said:

Seal issues are base oil compatibility issues. Natural rubbers do not like esters. But base oil is not part of the Dexos III or VI spec so.....???? 

 

The biggest difference between III and VI is viscosity. The friction package must be nearly the same as VI is backward compatible. 

 

 

That isn't confusing or anything.

Exactly!!!  And backwards compatible explains the rest.  Or at the very least 1% of it , right.  You gotta love these trucks and there clarification of fluids and specs outside of the factory choices right(I can only assume the other brands are similar at the very least too tho right.)

 

 

You can believe, I've done many many hours of reading on fluids and fluid specs in my Duramax years since 2006ish among many other issues and whatnot.  It is almost worse than a YouTube spiral. And much worse and expensive than clickbait in its worst form.  True story....  but i digress.......

Edited September 12, 2021 by THE YETI

[Grumpy Bear]

3 hours ago, THE YETI said:

Exactly!!!  And backwards compatible explains the rest.  Or at the very least 1% of it , right.  You gotta love these trucks and there clarification of fluids and specs outside of the factory choices right(I can only assume the other brands are similar at the very least too tho right.)

 

 

You can believe, I've done many many hours of reading on fluids and fluid specs in my Duramax years since 2006ish among many other issues and whatnot.  It is almost worse than a YouTube spiral. And much worse and expensive than clickbait in its worst form.  True story....  but i digress.......

 

16 hours ago, THE YETI said:

So I come from the Duramax world.  I've always bought Transynd by the 5 gallon pail.  Is Transynd a recommended option for this new 2021 HD 6 speed gas trucks?

 

As true as the first quote is you question was???? Is it recommended? Right? 

 

This got off the rails when we say "wont work" vs "not recommended". Not quite the same thing. 

 

https://www.merchant-automotive.com/blog/duradrivehd

 

 

Edited September 12, 2021 by Grumpy Bear

[THE YETI]

6 hours ago, Grumpy Bear said:

 

 

As true as the first quote is you question was???? Is it recommended? Right? 

 

This got off the rails when we say "wont work" vs "not recommended". Not quite the same thing. 

 

https://www.merchant-automotive.com/blog/duradrivehd

 

 

That is 100% true.  Not the same thing at all.  Thanks for the link. That is some good informative reading for the Duramax guys.

Edited September 12, 2021 by THE YETI