MerconV ATF?

2000 Ford F150, V8, 4.6L, auto transmission - 110K miles. Truck is in great shape that I just purchased to replace an older F150. The ATF is due for a change. I checked the owners manual and it lists 2 different automatic transmissions. The manual specifically states the following: “Some transmission fluids may be labeled as dual usage, such as MERCON and MERCON V. These dual usage fluids are not to be used in an automatic transmission that requires use of the MERCON type”. The problem I’m having is that I have no idea how to locate which transmission that I have. I’ve looked on and all around the pan and bell housing and can’t find any identifying numbers at all. I’m not sure if I’m reading into this too much because I would have just used Mercon V (which every Ford that I have in the family uses). Would anyone know which fluid to use ??

Are you sure that’s what it says? It doesn’t make any sense. Mercon V is the latest version of Mercon and replaces it. So Ford will tell you to use Merc V anytime Merc was specified. It doesn’t work in reverse though. If your manual / dipstick says Mercon V you can’t use Mercon.

The things that don’t mix are Mercon V and Mercon SP. You can’t use V if your spec is SP and vice versa.

The statement that “dual usage fluids are not to be used in an automatic transmission that requires use of the MERCON type” also makes no sense. Back before Dexron VI (GM spec), Mercon & Dexron were basically the same fluid. That’s why every auto parts store will have various brands of Dex/Merc.

If you can’t sort it out from the manual just take your VIN # to a Ford dealer. They’ll probably sell you a bunch of Merc V.

I copied and pasted that exact phrase from the original (electronic version) of the 2000 F150 owner’s manual. That’s why I’m asking the question because it makes no sense at all.

It says that some fluids may be labelled as dual usage. That applies to the fluid, not the transmission. What I read that to say is that you shouldn’t use a fluid if it says both MERCON and MERCON V.

The manual should specify exactly which fluid to use. Use that, and don’t use something that lists any other specification. Or visit a Ford dealer and take the VIN. It should be printed on the insurance card.

It won’t be long before 'Automotive Lubricants & Fluids" retail shops open that stock EVERY conceivable type and specification of liquid found in cars and trucks… The parts stores have run out of shelf-space required to stock all these “special” fluids…

Look on the transmission dipstick. Sometimes it states the transmission fluid to use.


Use Mercon V. The original fill does depend on which transmission your truck has but Mercon V has replaced Mercon. From a bulletin dated 07-24-2006;


Beginning immediately all automatic transmission / transaxle applications requiring MERCON® can now be serviced using MERCON® V or MERCON® Automatic Transmission Fluid or dual usage fluids labeled MERCON® / MERCON® V. After July 1, 2007, MERCON® Automatic Transmission Fluid will no longer be manufactured, therefore, availability of this fluid will only continue for however long it takes to deplete what remains in inventory.

Thanks everyone for the info - Mercon V it is (forgot all about the dipstick labeling, too).

Well now, here’s a conundrum.
Back in the day, transmissions and transfer cases took Dexron III which became Mercon. They both still took the Mercon.
– Then Mercon became Mercon V. —
NOW on the Mercon V bottle it clearly states " not to be used it transfer cases requiring Mercon. "

So Ford now sells a bottle labeled " Transfer case fluid"

I wonder, does logic project that " transfer case fluid " therefore is just Mercon/Dexron III ?

As usual the labels are ambiguous and secretive.
AND as the industry supercedes the parts numbers over and over, what they can’t touch is the older owner’s manuals hidden in every glove box with old info.

what they can't touch is the older owner's manuals hidden in every glove box with old info.

Luckily nobody reads those. :o)

Shelf space and shelf life… How far off can Mercon VI be???

There are 2 types of fluid for fords transmissions. The old version would be bad for a new transmission. It tends to be corrosive to elements in the transmission. I can only hope transman comes along.

What “elements”??? I don’t think ATF, any type, is corrosive to anything…You take a transmission apart, they all look pretty much the same inside…Steel is steel, iron is iron, aluminum is aluminum…ATF is oil …

My memory is real hazy on this, but I vaguely remember a Ford bulletin about a bad batch of transmission fluid sometime around 2000 and up.
IF your vehicle is an affected one maybe the bad fluid has been changed out already but doing it again anyway is not a bad idea at all even if it has. Maybe someone could verify this beyond all doubt.

Speaking of fluids, look at the different types of anti-freeze Ford recommends. It seems like every year and engine uses a different spec fluid. They must have 15 or 20 different types. No wonder people get confused.

The 4R100 uses Mercon where the 4R70W uses Mercon V. You need to know what type of transmission you have. Count the pan bolts and let me know how many you have. This is what they came with.


It shouldn’t matter either way as, according to Ford Merc V goes into anything originally on a Merc spec. There’s also really no such thing as Mercon anymore, as it really meant a fluid produced under a Ford license to Ford specs. Ford stopped those licenses when Merc V came along, and announced that Merc V should go in all Merc applications. What’s left for Mercon is any number of brands putting out a Dex III/Merc but since neither Dexron III nor Mercon are licensed anymore, exactly what that means can be a little ambiguous.

What I am trying to find out is what kind of transmission the OP has because the 4R100 of that year called for Mercon as a replacement where the 4R70W of the same year called for Mercon V as a replacement. If the OP has a 4R100 and there is any chance that there is Mercon in it its going to need a full fluid exchange. Its not a good idea to mix the two.


I had never heard the bit about not mixing the two, so I’m glad you mentioned it. One would think Ford would be obvious about such info when putting out their new fluid specs.

It’s not a FORD issue at all.
It’s an industry wide well kept secret as to which fluids are compatible or not.
Years ago Ford got in legal trouble when listing their fluid as ‘‘type H’’ when in fact it was just Dexron III.

At the parts houses you can get a multi-vehicle fluid that says on its label ;

Recomended for use in ;
GM Dexron II, Dexron III, Dexron VI
Ford Mercon LV
Toyota/Lexus type T, T II, T IV, WS ( except hybrid )
Honda/Acura ATF Z1 ( excep CVT )
Nissan/Infinity Matic D, Matic J, Matic K, Matic S
Hyundai/Kia SP II, SP III
BMW 7045E, ETL 8072B, LA2634, LT71141
Alison C4, TES 389
Mercedes NAG 1
Volvo 1161521, 1161540, 97340, 1273.41
VW/Audi G-052-025-A2, G-052-162A1

On my shelves in inventory I have ;
Mercon V
Mercon LV
Premium ATF
synthetic Mercon
transfer case fluid
Dexron VI for GM
ATF +4 for Chryslers
plus I still have 300 gallons of Mercon/Dexron III

Somebody out there make up your dang minds for god’s sake !

Pretty maddening isn’t it? Ranks right up there with the 9000 varieties of spark plugs. :wink: