Mercon Confusing specs and hard to find Mercon V

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I am trying to find some Mercon fluid for my 4R100 in my 2000 Excursion. The one quart bottles are like $4 a quart. I can't find anything at Walmart in the gallon jug but Dex/Merc but then it says not to use in transmissions requiring Mercon and Mercon V so why the Dex/Merc lable. Is Dexron III the same as Mercon?

Perry
 
Use only Mercon V rated fluid in your transmission unless you want to rebuild it.

You can use Mercon V in lower rated mercon requirement like III but can't use a Mercon III rated oil in a V application.

Do not use Dexron in your transmission.

Try Castrol or Valvoline brand, or go to your local transmission shop or Ford and see what they are charging.

Personally I would use Motorcraft transmission fluid from Ford, it's very very good stuff for your application even if they want to bend you over for it.
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Also consider a Magnefine filter which your Ford dealer should carry. It will vastly improve the life of your transmission and OCI.
 
Straight from the owners manual that I just downloaded.

MERCON and MERCON V type fluids are not interchangeable.
DO NOT mix MERCON and MERCON V. Use of a transmission
fluid that indicates dual usage (MERCON and MERCON V) in
an automatic transmission application requiring MERCON may
cause transmission damage. Use of any fluid other than the
recommended fluid may cause transmission damage.


So I guess DexII/Merc is ok then. It says not to use Mercon V or Mercon/Mercon V fluids. Mine calls for straight MERCON.

Perry
 
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since your download has been printed ford has said mercon V should be used in all apps originally speced for mercon.
i know it can be quite confusing, but mercon V will work quite well in your app
i had an 01 ex and i used mobil 1 syn atf (mercon V) for 120,000 mi.
 
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perry, you must have mis-read the label. The old Dexron III and Mercon fluids were in fact the same thing. Now, since GM no longer licenses Dexron III and Ford no longer licenses Mercon, the aftermarket is calling them D/M or DIII/M or DexMerc. There's no way the label said not to use it in a transmission that specifies Mercon, although as stated above you shouldn't use it in a transmission that specs Mercon V.

Anyway, I second what roadrunner1 said ^^^. Ford now states that Mercon V is the proper fluid to use in all transmissions and P/S units that originally spec'd plain Mercon. You can still use the DexMerc stuff, but you'll have to change it more often.

On a side note, I also questioned why they originally said it was a big no-no, now they say go ahead and use it. I bought a couple of cases of plain Mercon before it disappeared and I've been using it where spec'd but sooner or later I'm gonna have to make the switch...
 
Originally Posted By: tig1
M1 ATF works very well in Fords requiring Merc V.


I had great luck in a Ford Freestar with Mobil 1.
 
Our local Sams had Havoline DM3 (Dex/Merc) ATF for $1.13/qt. (12 qt case) Hard to beat that for a good fluid that meets the spec you need.
 
Perry, If you use Dex in about 8k miles you will have a feeling like you are driving with your parking brake not fully released.
I speak from experience. Use Mercon V fluid.
 
What is the problem here? Mercon and Mercon V can be found at ANY auto parts in the USA and every walmart I have ever seen.

Problem solved.
 
Well I ended up doing a total flush with Castrol DIII/MERC. I may go to MERC V at some point. I wanted to figure out if the torque converter lockup buzz/rattle would be fixed by a fluid change before I spend more$$ on MERC V. It turns out that a fluid change did fix the problem. I think I dodged a bullet on that one since this was a used vehicle. The old fluid was turning brown and did not smell too good. I pulled the pan as well to see what was going on inside the trans and it was clean as a whistle other than a little bit of steel fileing on the magnet(expected). There was no Aluminum or clutch residue.

I used to get transmission fluid from Sam's club but they stopped carrying it here.

Perry
 
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Originally Posted By: perryg114
MERCON and MERCON V type fluids are not interchangeable.
DO NOT mix MERCON and MERCON V. Use of a transmission
fluid that indicates dual usage (MERCON and MERCON V) in
an automatic transmission application requiring MERCON may
cause transmission damage. Use of any fluid other than the
recommended fluid may cause transmission damage.


That is only applicable to the Motorcraft fluids being offered at the time the owner's manual was printed. When Ford reformulated Mercon V, they completely did away with their Mercon fluid and made their Mercon V backwards compatible.

The old Motorcraft website had the fluid compatibility charts posted, and Mercon V was back spec'd.

Modern Mercon V fluids are OK to use in your 4R100.
 
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