Originally Posted By: bdcardinal
Originally Posted By: Luber216
It's definitely Mercon V. Mercon SP wasn't factory filled in a Ford Transmission until '06 or '07 let alone even developed for the '04 year. Just get some ATF and a good shudder guard that makes AF3 meet Mercon V specs unless you actually want to go synthetic which is just better anyway. And most synthetic ATFs far exceed the Mercon V spec
This is completely incorrect advice. Whoever told you that was wrong and should not be trusted for information.
I could not agree more with you bc.
Again, here is the official Ford manual; check page 286:
http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/04f23og3e.pdf
CLEARLY states Mercon SP. That goes all the way back to 2003 for the 5R110. 2003 was a transitional year; both the 7.3 with the 4R100 and the 6.0 with the 5R110 were offered. The "Mercon" was for the 4R100; the "SP" was for the 5R110. By 2004, all SuperDuty diesel trucks were only available with the 5R110 auto or ZF manual. If you closely review the iterations of manuals in 2003, you'll see FIVE different printings. As they progressed into the 5R110, it has ALWAYS called for "SP" from late 2003 to 2007. Even in 2008 the 5R110 called for SP. Only in 2009 & 2010 did they switch to the LV for that trans, and as noted, that was likely because they intended to do away with the SP, but have since decided to still offer it.
That SP fluid was developed for use with that 5R110 trans. It is still offered. That would be my first choice. LV, while being a decent fluid, was the "afterthought" for the 5R110 that Ford had when they initially intended to do away with SP, which they have not. However, Ford does not spec the SP and instead specs the LV all the way.
In short, either the SP or LV will work. I would prefer the SP if it were my truck, as that was the original spec'd fluid, and is still available.
If that is not clear enough by now, I don't know what else we can say.