Blending Dexron, Mercon V and Multi Fluids?

[Rock_Hudstone]

This question has probably been answered before but the search function leaves much to be desired.

Anyway, from what I understand blending Dexron III, Mercon V, or Multi vehicle domestic ATF in a older model GM trans is allowable.

However, what are the pros and cons of doing so, if any?
Which is the best fluid?

 

[The Critic]

Dexron VI is the best fluid in a GM transmission that calls for Dexron III or prior.

There's no advantage to blending fluids.

 

[Steelers]

Blending different fluids such as when doing a partial change out won't hurt anything as long as the fluid you're adding meets your makers specs. What is the best fluid is a loaded question. Need to know car/make. Generally, Amsoil or Mobil 1 multi-vehicle would be my pick in a newer car that I intended to keep. Your GM is "older" and would do fine on any Dex III. Walmart sells jugs of Supertech Dex III/Mercon on the cheap if you're looking to save a buck.

 

[The Critic]

Dexron III no longer exists in a licensed form. It would be unwise to purchase any "DEX/MERC equivalent" fluids as the contents are unknown. Dexron VI is the only approved service fill for GM hydramatic transmissions at this time.

 

[Drew2000]

Originally Posted By: The Critic
Dexron III no longer exists in a licensed form. It would be unwise to purchase any "DEX/MERC equivalent" fluids as the contents are unknown. Dexron VI is the only approved service fill for GM hydramatic transmissions at this time.


What about the DexIII/Mercon that still meet the Allison C-4 spec? I really can't see the major brands like SOPUS or Exxon/Mobil cutting the quality on a fluid that's pretty cheap to manufacture in the first place.

I did send a e-mail to Pennzoil (SOPUS) and the reply was it's the exact same ATF as previous "licensed" versions.
http://www.pzlqs.com/Tech/Pdsheet/Domest...issionFluid.pdf

Drew

 

[The Critic]

I guess it depends how much you trust Pennzoil.

Besides, there's little reason (aside from cost) to not upgrade to Dexron-VI. Dexron-VI is a far superior fluid to Dexron-III(H).

 

[Rock_Hudstone]

Originally Posted By: Steelers
Blending different fluids such as when doing a partial change out won't hurt anything as long as the fluid you're adding meets your makers specs. What is the best fluid is a loaded question.

I worded that question wrong, I meant to say which fluid grades are better, not brands.

 

[unDummy]

Trust Pennzoil? or do you trust a silly GM license?

Any similarly spec'd fluids can be mixed.

Just because a license doesn't exist doesn't mean the fluid formula or requirements were forgotten.

Not everyone wants to spend $7 a quart of DexronVI when a gallon of Supertech costs the same and meets the requirement of those older vehicles.

But, I do recommend upgrades if they are in your budget. A blend, like Mercon-V or multivehicle ATF, or a full synthetic should be considered. Cost depends on driving style, transmission history, budget, expectations...... Even cheap fluid with a reasonable change interval will provide a decent transmission life.

 

[mikeg5]

well my toyota tacoma calls for DEXIII and i was told NOT to use DEXIV bc no one knows if it will harm the older yota transmissions... so i will stick with maxlife dexIII or M1 dexIII....

 

[lewk]

Many private companies products are not liscensed but their products are good. My concern would be the use of additives not the OTC product.