4T60, Dex-VI or Synthetic Dex-III?

[pitzel]

My GM 4T60 (aka Hydramatic 440-T4) 4-speed transaxle will need a pan drop and partial fluid change in the next little while.

I basically have a few choices that aren't hard to find around here:

Dexron-VI -- Mobil, ACDelco (OEM)

"Synthetic" Dexron-III "compatible" ATF -- either Mobil-1, or the Co-Op full PAO synthetic with a -66degC pour point and "meets the performance requirements of Dexron III". (https://www.coopconnection.ca/wps/wcm/connect/1d40e050-bbf0-4288-84af-6e1cad9428a2/Lubricant+Petro+Specs%5B1%5D.pdf?MOD=AJPERES)

(PDF page 21)

I live in Canada and the ambient temperature does get down to around -40C. Engine already runs Esso XD-3 0W-30 (superceded by Mobil Delvac 222 0W-30, but I still have a stockpile of the older stuff) with great success.

Not trying to solve any problems with shifting or anything. The pure synthetics cost 50-60% more to acquire. But the new spec Dex-VI fluids are already synthetic blends, and as Molakule has posted in an earlier post, have a significantly improved additive package.

(BTW, in case anyone remembers me from about a decade ago, 120k km's later on 2 XD-3 0W-30 oil changes in the same car!!! Yes, that's right, 38k miles per oil change!! No sludge either! And fuel efficiency on a consistent 500 mile trip I make is unchanged from that of a decade ago!)

 

[RobtE]

Originally Posted By: pitzel
"Synthetic" Dexron-III "compatible" ATF -- either Mobil-1, or the Co-Op full PAO synthetic with a -66degC pour point and "meets the performance requirements of Dexron III".

I live in Canada and the ambient temperature does get down to around -40C. Engine already runs Esso XD-3 0W-30 (superceded by Mobil Delvac 222 0W-30, but I still have a stockpile of the older stuff) with great success.


I live in an area with moderate temperatures, but I travel in areas where -20F is not an uncommon experience.

I looked at a dozen or so ATFs and selected the Red Line D4 and D6. Their low temperature characteristics were the best I could find.

The CO-OP Sonic ATF SL appears to track the Red Line D4 - the viscosity is in line with Dexron III and if their literature is accurate they achieve low temperature performance by using PAO instead of Group III and a pour point depressant.

On paper at least it is worth considering.

Dexron VI is a lower viscosity product than the CO-OP Sonic ATF SL. My understanding is that all of the licensed products are Group III. It is "thinner" at all temperatures and would not exhibit the same extreme low temperature characteristics.

Mobil Dexron VI

 

[CharBaby]

Well, I do understand that the new Dexron VI is backward compatable but, I love Mobil 1 ATF also! It's a tough call to say the least. I guess it comes down to money!

 

[MolaKule]

Quote:
My understanding is that all of the licensed products are Group III.


Actually, most use majority GroupIII with some minority base oil components.

The boutique blenders use majority PAO with minority esters with the PI packs.

 

[pitzel]

MolaKule, what's more important? The base oil, or the additive package?

Could a really good additive package make up for a lesser-quality base oil? Could a higher-quality base oil make up for a lesser-quality additive package?

Do ATFs use pour point depressants and viscosity modifiers to the extent that engine oils formulated with conventional basestocks (ie: lower-VI oils) do?

I know there's not a 'right' answer, and ideally, one would pick a Dex-VI pure PAO if such were available/licensed.

Maybe a better question to ask is, how far away from Dex-VI spec are fluids like Mobil-1 Synthetic ATF?

 

[pitzel]

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/825873/1

Hmmm sounds like that thread has a poster who has a pretty emphatic view on what to use in the 4T60-E, albeit an upgraded version of the 4T60.

So Dex-VI its probably going to be.

 

[MolaKule]

Originally Posted By: pitzel
MolaKule, what's more important? The base oil, or the additive package?


You can't have one without the other. Both are important to oxidative stability.

Quote:
Could a really good additive package make up for a lesser-quality base oil? Could a higher-quality base oil make up for a lesser-quality additive package?


Short answer is, no.

Quote:
Do ATFs use pour point depressants and viscosity modifiers to the extent that engine oils formulated with conventional basestocks (ie: lower-VI oils) do?


ATFs have a different type of VII. Each type of lubricant has a specific base oil mix and PI package.



Quote:
Maybe a better question to ask is, how far away from Dex-VI spec are fluids like Mobil-1 Synthetic ATF?


Mobil 1™ Synthetic ATF

http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_1_Synthetic_ATF.aspx

is an older DexIII/Merc formulation and does NOT meet the same viscosity or stability specifications as a DexVI.

However,

Mobil 1 Dexron VI

http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_Dexron-VI_ATF.aspx

does meet the viscosity and stability specifications.

 

[pitzel]

Oh wow, didn't know there was such thing as M1 Dex-IV-compliant ATF. Don't see it on the shelves here in Canada.

Thank you very much! Now I have more stuff to think about!

edit: Err, that's just "Mobil" Dex-IV, not Mobil 1 Dex-IV (so just a synthetic blend). Though I probably was going to go with that product anyways, although I am told that I can get the Petro Canada Dex-IV stuff as well here.

 

[Garak]

Up here, it's Mobil Super Dexron-VI, and yes, Petro-Canada sells a licensed product, too. I have some of the Mobil stuff on my shelf. Aside from Imperial Oil, the easiest place to find it will be Partsource or Canadian Tire. Imperial Oil would probably have you buy a box of jugs, rather than a single jug.

 

[MolaKule]

Historically, Petro-Canada was the first company to blend and distribute DexronVI.

Petro-Canada worked with the Afton additive company to develop DexronVI according to GM specifcations.

 

[Garak]

Yep, and Petro-Canada is pretty proud to proclaim that fact in a few spots on their site and sheets.