Dex III (H) Which brand most likely to meet spec?

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JDD

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I am not inclined to use Dex VI in my 1996 Yukon's 4L60E--It has the original trans AFAIK and it has 148K miles, and seems to work reasonably well. I don't do any towing. I just want to try to keep it alive a few more years with Dex III. Since there is no GM support, how do I know if the Dex III I buy 'meets' the 'H' spec of Dex III, which is clearly improved over the other earlier Dex III specs. What brand(s) are likely to be H? In theory, any manufacturer could fill the bottle with just about anything and say it's Dex/Merc, but which spec?? Any thoughts on which brands would likely be H? I have used Valvoline Dex/Merc and Pennzoil Dex/Merc in the past in this vehicle.

Note: I am not inclined to use Mobil 1 ATF either. There's too much negative noise about that fluid for this transmission for me to want to use it for this vehicle.
 
i have heard penzoil merc/dex is unchanged formula since the de-licensing.

also heard valvoline merc/dex blue bottle is the original unchanged formula.
 
have heard, but how can we be sure?

Especially since pennzoil is sold at wal-mart, how do we know price pressure hasnt changed it? For products with no governing body to meet like dex III, id be a bit wary. That said, it surely still meets dex III, and Id personally be changing out often if possible...
 
Not sure what's available to you, but ACDelco ATF Type III (H) is still being sold here (made in USA). This is what I used when I did the Avalanche, although prior to that I used Quaker State Dexron III in the green bottles.
 
Sorry i cant help with your questions but i can tell you that i 3 chevy trucks now and all of them are over 195k miles. 99 suburban, 93 1500, 01 blazer. I have used M1 in my blazer for 175k miles and never had an issue. the others have always gotten apx 30k changes with coastal DEX 3 from AZ or ST from WM they are fine. The only thing i have ever had issues with was the Valvoline Dex 6. I bought a case and ended up giving the rest to my dad.
 
Yes AC Delco DexMerc is good stuff and sold here for about $4.00 a quart.


I noticed that my local Wallmart sells Castrol Dex/Merc for $3.50 a quart.
http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=82915486&contentId=7027043

pivehcarelub10118.jpg
 
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Any Allison TES389 or TES295 will work great.

Any Mercon-V is usually an upgrade above Dexron-IIIH.

Any full synthetic universal/multivehicle ATF is an usually an upgrade over Mercon-V.

Stick with a name brand fluid. You rely on their reputation.

I have never seen a Mobil-1 ATF issue. Heard about a few. But, there were always 'other' variables that needed to be addressed. Don't fall for the hearsay.

Depending on age and driving style, don't forget that a TAPs reset might be required with the new fluid.

Two, relatively affordable fluids online that I'd recommend, are Schaeffers 204s and Amalie/xcel/wolfshead Full Synthetic.

And, there isn't anything wrong with DexronVI.

Locally, Valvoline Maxlife from wallyworld at $4 a quart would be an easy choice.

If you stick with a generic Dex/Merc, D/M, or domestic type ATF, toss in a bottle of Lubegard or Smartblend Red. If the generic ATF has served your driving style well for the past 148k, then it still will. Mobil, Pennzoil, Castrol, Havoline, mineral D/M ATF's will suffice.
 
Originally Posted By: unDummy


Any Mercon-V is usually an upgrade above Dexron-IIIH.





This caught my attention---so Merc V is a viable choice for this vehicle?---I guess it makes sense since it is the replacement for Merc and the DEX/Merc Spec is(was) similar. Anyone run Merc V in a 4L60?
 
ATF meeting the spec for Allison TES 389 IS Dexron-III(H) with a different name. Same fluid, different name on the spec.

Allison requires a TES 389 fluid in transmissions that were previously spec'ed for Dexron-III (where Dex-VI isn't suitable), and where the owner doesn't want to use syn TES 295 (Transynd).
 
Originally Posted By: JDD
Originally Posted By: unDummy
Any Mercon-V is usually an upgrade above Dexron-IIIH.


This caught my attention---so Merc V is a viable choice for this vehicle?---I guess it makes sense since it is the replacement for Merc and the DEX/Merc Spec is(was) similar. Anyone run Merc V in a 4L60?


I would use the Mercon V.

Johnny confirmed a while ago the Penzoil ATF it still DecIII(H) but I would still use the Mecon V over that
 
IMO the dex III vs Mercon V utilization needs some more discussion.

If Mercon V (a full syn fluid, correct?) is to be used, why not use dex VI instead?

If you want a robust dex III, why not use the transynd 295 fluid?

Im missing a connection between why mercon V should beused in a dex-specced product when it is a different specification. My impression was that while Merc and dex III were close enough, Merc V was a divergence.
 
I should fess up to what I am trying to accomplish with the original question. I have a 15 yr old 4L60E that I want to be a 20 yr old 4L60E when it grows up. I'm caught betewen a dilemma that may just be between my two ears. I am not comfortable (yet) with Dex VI just due to age/mileage of the trans. VI is just so much thinner and I suspect that trans has normal wear. But, I would like better low temp performance/protection. It has not been above freezing for weeks here and the Yukon is parked outside. Lately it has been single digits when I start in the morning. So, the H spec Dex III is what I wanted to make sure that if I stay with III that I would at least get the best specc'd fluid. Ideally what I want is better low temp protection, but not too thin because of the age/wear resulting in weird shifts and accelerated wear---does that make sense? That's why the Merc V post caught my eye--sort of a tweener between Dex III and VI and an upgrade over the III. I've just never changed from the ATF spec fluid on any vehicle ever.
Also, I did have a drain plug installed on the pan last year when I had the filter done, so fluid changeover will be pretty easy. I guess I want someone to talk me down off the ledge---that it's OK to switch to a different/better fluid even on a trans this old.
 
Originally Posted By: JHZR2
IMO the dex III vs Mercon V utilization needs some more discussion.

If Mercon V (a full syn fluid, correct?) is to be used, why not use dex VI instead?

If you want a robust dex III, why not use the transynd 295 fluid?

I'm missing a connection between why mercon V should be used in a dex-specced product when it is a different specification. My impression was that while Merc and dex III were close enough, Merc V was a divergence.


Just think logically. Mercon and Dexron III were almost the same fluid. So close that they had the same fluid sold for both, Now Mercon V is a direct replacement for Mercon. If it can be a direct replacement for Mercon,(and Mercon and Dexron II are the same) it can also be a direct replacement for Dexron III
 
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Originally Posted By: JHZR2
IMO the dex III vs Mercon V utilization needs some more discussion.

If Mercon V (a full syn fluid, correct?) is to be used, why not use dex VI instead?



http://www.lifeautomotive.com/pdfs/history_of_atf.pdf
Low Temp Brookfield viscosity-- Dex III 20000, Merc V 13000, Dex VI 8400. The Merc V is sort of a tweener vis if I am understanding it correctly.
 
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