Mercon V specs vs. Dex/Merc III

[Jarpin]

For the last 4 years, I've been using Merc V in a 90's Toyota which calls for use of OEM stuff or Dex/Merc III. Zero shifting issues, but is it safe to continue using based on it's abilities? Thanks.

 

[GSCJR]

Yes.

 

[ka9mnx]

When your vehicle was produced Mercon and Dex II/III were basically the same and interchangeable. Mercon V is not a recommended replacement for Dex II/III.

BTW: There is no Merc III

 

[brianl703]

When your vehicle was produced Mercon and Dex II/III were basically the same and interchangeable. Mercon V is not a recommended replacement for Dex II/III.

Mercon V was, in fact, recommended as a replacement for Dex II/III by pretty much every company that made it back about 15-20 years ago.

For example, this from the 2014 data sheet for Havoline ATF Mercon V:

Valvoline currently says this about their Mercon V:

• SUITABLE FOR Ford Mercon V and Mercon, Dexron-II and Dexron-III, Caterpillar TO-2, Allison C-4, and some power steering fluid applications.

 

[69GTX]

When your vehicle was produced Mercon and Dex II/III were basically the same and interchangeable. Mercon V is not a recommended replacement for Dex II/III.

BTW: There is no Merc III

Ford came up with Mercon V to be a replacement and upgrade to all their transmissions using Dex III dino oil. It has a slightly better
additive package but is a semi-synthetic, thereby giving it better protection from heat oxidation and shearing. It lasts longer than
Dex III under the same heat and stress conditions. My 1997 Lincoln was specced for Dex III. By 2000/2001 the same car was using Mercon V.
Something tells me that this also part of boosting the CAFE mileage standards in that 2000/2001 period. Ford also changed a number of their basic motor oil specs from 5w-30 to 5w-20.....only for fleet mileage improvement....not for engine protection or increased engine life.

 

[Lubener]

For the last 4 years, I've been using Merc V in a 90's Toyota which calls for use of OEM stuff or Dex/Merc III. Zero shifting issues, but is it safe to continue using based on it's abilities? Thanks.

Wouldn't you think if it wasn't safe, you would have had issues by now?

 

[Jarpin]

Wouldn't you think if it wasn't safe, you would have had issues by now?

Does it hurt simply to ask???

 

[Lubener]

Does it hurt simply to ask???

Only when common sense does not prevail.

 

[CleanSump]

Legit question. Good guys answered it.

 

[Jarpin]

Only when common sense does not prevail.

Perhaps you are all seeing and all knowing of what is happening inside a transmission at the particle level in terms of frictional wear on the planetary gears or solenoids at ALL times. Most of us do not, hence the question. If you want to engage in endless semantics, let's go to the general discussion forum.