the book says use motorcraft mercon ATF. a manual online says motorcraft mercon multi purpose automatic transmission fluid xt-2-qdx or mercon.

so the dex/mer or dexIII/mer howeverit is the same stuff?

 

I believe that you can use any fluid that is Mercon compliant. For example, I used Amsoil AFT that can be found here.

 

so dealer gives me mercon V and if you looke it up I believe mercon atf was updated in 2007 by ford to mercon v only problem is on the mercon v ford bottle it says Do Not use in transfer cases lol now what?

 

now I called another dealer and said he gave me the wrong stuff

 

Mercon V technically replaced Mercon, as Ford no longer officially produces it. You can still buy regular old Dex/Merc. Mercon V is correct to current Ford specs, Personally I run the Mobile 1 which is compatible with many different ATF's.

 

For the Transfer Case, the currently available official Ford fluid to use is called "Transfer Case Fluid", Motorcraft part number XL-12.




On the XL-12 Transfer Case Fluid bottle, Ford states:

"For use in transfer cases where MERCON® ATF was previously recommended. "


The confusion is understandable. Way back when Ford first introduced Mercon V, Ford cautioned everyone, saying that Mercon V may not be backward compatible with Mercon. Even our resident transmission expert, Mark Kovalsky, is on record numerous times in the archives of several forums stating emphatically do NOT use Mercon V in the 4R100, back in the days when he was working for Ford.

However, then, Ford did an about face (probably after sufficient field testing determined no detriment) and announced that Mercon V is indeed not only backwardly compatible with Mercon, it is in fact BETTER than Mercon for the applications that used to call for Mercon. And seemingly just to make sure that transmission shops didn't use Mercon in applications designed for Mercon V, Ford announced the sunset of Mercon licensing. Accordingly, Mark changed his recommendations (while still working for Ford) to suggest Mercon V for all Super Duty automatic transmission applications formerly calling for Mercon.

The idea that Mercon V is now appropriate for all applications calling for Mercon is where everyone gets tripped up... because in earlier model Superduties, the part time transfer cases (NV271 and NV273) call for Mercon fluid. Accordingly, people have put in Mercon V in the transfer cases. But this isn't what Ford recommends. Ford probably could have been clearer about this earlier on, but Ford appears to be making up for this lack of clarity by being really clear now:

On all Mercon V bottles, Ford states:

"Do not use in transfer cases where MERCON® ATF was previously recommended."


Beyond doing what you've already done, which is to read the bottle, unlike what the dealership personnel that you've dealt with appear to have done, an alternative way to confirm this is to look at an owners manual for a later model Super Duty, built after Ford ceased issuing the Mercon specification license to fluid formulators.

With the same model transfer case (NV271 and NV273), Ford puts in writing their recommendation that Super Duty owners use Motorcraft XL-12 Transfer Case Fluid in the transfer case.

Transfer Case Fluid in the transfer case. Makes sense to me!

 

What I find interesting is inside is GEARS and CHAIN that is it....no clutches, no bull$h*t that requires specific additives.....this is what I find puzzling that it has to be a specific type of ATF.

Probably overthinking it if you ask me.

 

For whatever reason, Ford made this determination... that is likely at the inconvenience and consternation of the entire dealership service network, due to the hassle of stocking yet another fluid, where they would otherwise be able to use Mercon V from bulk 55 gallon drums at a much lower cost per quart.

Whether or not Ford engineers are over thinking it, I have neither the specific education nor sufficient access to statistically significant service data to "under think" Ford's recommendation. I am continuing to use my stockpile of full synthetic Mercon, but if I were in the OP's shoes and needed new fluid from Ford, I'd get the Motorcraft XL-12 as recommended.

There is likely a reason why Ford found that neither Mercon V, Mercon SP, nor any of at least 7 additional Ford drivetrain lubricants were acceptable enough in the gear and chain transfer case to not take advantage of the inherent economy in reducing SKU's and service complexity.

 

what they told me the mercon V can be used up until 2007 or so then they def want you to use the bottle pictured that says transfer case fluid which is more money than the mercon V ... we called another dealer and that's why they kinda said too. im not sure what t-case is in the 2003 f550 superduty. but I put two qts of the mercon V in right now . idk.........

 

You and I have the same transfer case... an NP271 Manual Shift on the Floor.

The NP273 is the same transfer case, with an electronic shift motor instead of a floor stick, called Electronic Shift on the Fly. (ESOF) The ESOF was not available in the F-550 until later years... I don't remember when later though.

 

yes manual floor shift and manual locking hubs

so am I safe with mercon V ? lol

 

Mercon V will be fine. I recently put Mobil1 ATF in mine which is equivelent to MerconV and it works as supposed to.

 

Funny how I wrote this and now they don't have XL-12 abd don't recommend Mercon V.

Currently others mentioned Mercon LV