Mercon III or V

[katsdad]

I have a 1990 F150, 4.9, Automatic. Should I use the III or V. I have read through several of the other posts and am not clear on what I should do. I can pick up Castrol's V for $1.25 a quart at a parts store that is closing or the Pennzoil III at Target for $1.89. Thanks for your input

Doug

 

[jjbula]

Call the Ford dealer and ask them. They may or may not support changing from Mercon to Mercon V.

I don't know what Mercon III is. Are you refering to a Dexron III/Mercon approved product?

Mercon V was not available before 1996 and I found out it is approved for my 1995 Windstar. The manual says Mercon but Ford says switch to the newer Mercon V.

Mercon V seems to only be offered as a synthetic blend.

 

[katsdad]

It is the DextronIII/Mercon I am referring to in comparison to the Mercon V.....Thanks

 

[widman]

Mercon V is backwards compatable to all previous versions. Normally not used because it is 2 x the price.

 

[MNgopher]

quote:

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Originally posted by widman:
Mercon V is backwards compatable to all previous versions. Normally not used because it is 2 x the price.

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Actually, that is not true. The 4R100 Transmission (used in Ford Superduty trucks, Vans, etc..) specifically disallows the use of Mercon V. It is a Mercon tranny only. Using the Mercon V leads to premature wear of various compenents in the 4R100 and eventually failure. Only use Mercon V in an approved application.

 

[widman]

Asside from Ford telling me they are backwards compatable,
Here is what Texaco says:
"Havoline Automatic Transmission Fluid MERCON V is fully approved for Ford MERCON V and MERCON applications as well as General Motors DEXRON-III.

It is manufactured from select base oils and additives that provide oxidation and thermal stability, friction control, load-carrying ability, corrosion and wear protection, and prevent the accumulation of deposits and the formation of sludge, varnish, and foam.

Compared to MERCON fluids, Havoline Automatic Transmission Fluid MERCON V has exceptional low temperature flow properties and enhanced protection against viscosity breakdown.

Under the most severe operating conditions, Havoline Automatic Transmission Fluid MERCON V:

maintains friction control for smooth shift action
retains low temperature fluidity and high temperature stability for long operating periods.
protects automatic transmission fluid coolers from corrosion.
practically eliminates transmission overhauls due to sludge, corrosion, wear of clutches and bands, gears and bearings, leakage past seals, and loss of frictional properties.

Applications

Havoline Automatic Transmission Fluid MERCON V is designed specifically for use in Ford Motor Company transmissions that require a MERCON V fluid. The enhanced properties of the MERCON V specification offer premium performance in MERCON or DEXRON-III applications."
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Here is what Chevron says in addition to something like the above:
"Chevron Automatic Transmission Fluid MERCON V meets or exceeds manufacturer's performance requirements
Ford MERCON, MERCON V
General Motors DEXRON-III

Chevron Automatic Transmission Fluid MERCON V has the following qualifications:

Ford MERCON M000601
Ford MERCON V M5000601
General Motors DEXRON-III G-34555 "

 

[MNgopher]

I guarantee Ford will not tell you Mercon V is backward compatible in all current transmissions. Specifically, the 4R100 in all Superduty trucks is a Mercon only transmission If a Ford dealership has told you this, then they are badly misinformed.

Ford has issued TSB's to remind dealers of this fact. Superduty owners with auto trannies and powerstrokes have enough to worry about where the tranny is concerned, and believe me, they are very concerned about having the wrong fluid in their transmissions.

The owners manuals specifically state that Mercon V is not an accepted fluid, and not to use a fluid that claims to meet both Mercon and Mercon V standards. This holds true even in 2002 models.

Fords applicability chart specifically disallows the use of Mercon V in any 4R100 transmission or earlier variants thereof.

 

[MNgopher]

quote:

---

Originally posted by MNgopher:
I guarantee Ford will not tell you Mercon V is backward compatible in all current transmissions. Specifically, the 4R100 in all Superduty trucks is a Mercon only transmission If a Ford dealership has told you this, then they are badly misinformed.

Ford has issued TSB's to remind dealers of this fact. Superduty owners with auto trannies and powerstrokes have enough to worry about where the tranny is concerned, and believe me, they are very concerned about having the wrong fluid in their transmissions.

The owners manuals specifically state that Mercon V is not an accepted fluid, and not to use a fluid that claims to meet both Mercon and Mercon V standards. This holds true even in 2002 models.

Fords applicability chart specifically disallows the use of Mercon V in any 4R100 transmission or earlier variants thereof.

---

 

[katsdad]

My question was in regards to a 1990 F150. I believe the V is for most Fords after 1977. My manual of course does not mention V. I was able to buy at $1.25 a quart and wanted to know if this was a better product to use other than the pre V Mercon. Called Ford and It can be used in my application. Not sure if it is better though.

 

[widman]

I just went to the service department at a Ford Dealer in Va. They said there is terrible confusion on this issue. They said that Mercon V can be used in any transmission that had Dexron/Mercon under the following conditions:
A transmission that had regular Dexron/Mercon can use Mercon V only if it is rebuilt. That too much of the additives from the Dexron/Mercon and fluid will remain in the seals unless it is rebuilt. Once rebuilt, all can use Mercon V, without exception.

 

[katsdad]

Well, I bought 2 cases of the castrol V for $30 this week. I have autoRX in the trans now...maybe that will take care of the possible seal problem mentioned.

Wonder how the V would cause a problem? I have read in several posts that the Lubegard product can give Dextron/Mercon the characteristics of V. Would that mean that Lubegard should not be used in pre-1997 vehicles?