will regular mercon cause shudder?

[Experdition]

DEXRON III/ Mercon will cause shudder!

Yes it will! Do not use DEXRON III/ MERC fluid!

DEXRON III is for chevy's! They made a multi use blend called Dexron III/ Merc, but it does not work like Motorcraft pure Mercon or pure mercon V.

Use only Merc V!

Let this be an end to this discussion!

 

[Lightnig]

Ok, you got me curious

What's the answer???

 

[Experdition]

The answer is yes, if the transmission had mercon v put in it then someone put the dex III/mercon in it, it would begin to shudder. And that shudder will start out mild and get worse and worse. For that matter, if you switch from the pure motorcraft mercon fluid to the dex III/ merc stuff it will cause you to have shudder issues as well. As in the case of a tranny that has never been serviced from the factory then you put in this dexron III/mercon stuff, it causes issues.

Once you go to mercon v you can never go back.

The only regular mercon you can get these days is the dexron III/ mercon multi use fluid. Notice it is Dexron III first, then mercon second. So that is the reason it causes this problem. The multi use fluid is no good anymore for these trucks because they are shudder prone to begin with and a crappy dexron/merc mashup is causing people to have problems. Especially when ford tells them in their owners manual to use mercon and they see mercon on the label they think it is OK.

Dont ever use that Dexron III / merc crap in a ford truck ever!

You dont need the synthetic high priced stuff, just real mercon v. it fixes the shudder instantly.

 

[whowey]

Each variation of the manufacturers respective formulas is based on their individual needs.

The Dexron name is a trade name of General Motors, just like the Mercon or Ford Type F is a trade name of Ford. The ATF+ name is the Chrysler's version.

Under the old system a tranny fluid manufacturer could lease the performance specs of the fluid they wanted to make and use the name. This is how the mullti-use fluids like Dex II/III/Mercon fluids came into being.

The performance specs for Dex II/III and Mercon are very close and the fluid will be more than sufficient for transmissions that require those fluids.

Fast forward a few years and we see a totally new set of performance specs. For Ford owners we see Mercon V and VI... These specifications required new transmission fluids as they are quite a bit more rigid than the old Mercon specifications.

What does this mean for us?? Well, in the shortest possible answer, What it means is that we have to use a fluid that meets the stricter Mercon V/VI specification and not the older fluid. Now... if you have a transmission in another vehicle that requires the older Mercon specification, you can use Mercon V in it. But not the other way around.

The Mercon VI specification is not another upgrade over the Mercon V. It is a lower viscosity specification for the transmissions that are designed for it. It is not intended for use in the transmissions that are not intended for it.

Mercon V is the correct specification for the 4R100. Mercon VI is the correct specification for the 4R70W.

 

[GaExpedition]

My expy had a bad shudder appear about a month or so ago during the 3-4 change, and at converter lockup. Changed tranny filter and filled her up with merconV. Shifts like a new tranny now. Mine is a 4R100 btw. Pretty sure merconV is also recommended for the 4R70W, but I will leave that to the experts, or your personal research on the matter.

 

[toms89]

Two pages out of my 2000 Ford Expedition owners manual:





It seems to contradict was has been stated as far as which transmissions use straight mercon vs mercon V.

I believe I read somewhere ford issued a service bulletin on the subject, as far as use of mercon V in earlier expys rated for straight mercon, but don't know where or what it is. Hopefully someone can post if they are aware of it.

The owners manual does make it somewhat clear that the fluids "dual rated" are not recommended for vehicles in which straight mercon was specified.

My dipstick does indicate Mercon, not Mercon V by the way. (4r100)

 

[toms89]

Found it!!!!

They reformulated mercon V to be compatible with the older straight mercon which is no longer available.

Tried to attach pdf but it was too large. Heres a link to view.

http://www.stangnet.com/images/stories/docs/sn95_TSBs/06-14-04.pdf

 

[toms89]

Maybe it would be a good idea to post the service bulletin pdf in a sticky in the tranny section?!

Mercon V to replace Mercon ATF in early expys.