Transmission/Axle Type

While I can't answer your question...I've a 03 and had same questions. Matter of fact what is stamped on my trans dip stick is wrong. For me to feel correct in all my fluids I found a VIN decoder to be most helpful. I don't have link but easy to find. I printed it out and keep by owners manual.

You have the 4R100 transmission.

If you're changing the fluid and the internal filter, be aware that there are two different transmission pans for the transmission, a deep and a shallow version, and the filters differ based on which pan style you have. You'll almost certainly have a deep pan and need the corresponding filter. The parts lookup at many auto parts stores might not know the difference or only have the shallow one in stock. Verify that the filters match up (particularly with regard to pickup tube length) to make sure you get the right one.

As for the differential fluid, I think it's a lifetime synthetic fluid...at least it is on my '98. It's the 4.10 rear end, if that helps.

Your E450 has the 4R100. All V10s do in fact, from 2000 until the TorqueShift came out in 2005 models.

It takes Mercon-V fluid.

I run 75w140 in the diff. There are other acceptable viscosities , but this provides the broadest protection range. Note that Ford requires full synthetic, otherwise you have to change the gear oil every 3,000 miles. But I think 75w140 only comes in synthetic anyways.

Changed our 2002 axle to 75W-140 Supertech (Walmart Brand) axle lube a couple years ago. Didn't want to remove the axle cover. Wasn't leaking and I didn't want trouble, especially with the large afternarket sway bar and track bar I installed on ours. With the lube warm and stirred right after a trip, sucked the lube out with an "Oil Boy" as used changing oil in boat engines. Started with the OB empty so I could measure what came out against the capacity spec. It matched. The WM lube comes in 1-quart bottles and I fitted hose to their squirt caps. Filling went pretty well, but next time, I'd put more cardboard down, and reach us to punch a hole in the bottom of each bottle, instead of trying to squeeze it. Good idea to have the new lube bottles in the sun, a warm room, or in hot water prior to filling.