Do you have the black housing on top of the engine as shown in the PDF you gave us the link to? Underneath near the oil pan is, on some Fords, an external transmission filter. It is inline in a cooler line, but is, I think, right in front of the bellhousing, under the oil pan.
Also, many diesel fuel filters are large and look like spin on oil filters.
The one on top looks easy, very similar to my 5 cyl Sprinter setup.
Charles
2007 Winnebago View 523H on a 2006 Dodge (Daimler-Chrysler aka Mercedes) Sprinter 3500 chassis. Bought Sept 2015 with 18K miles on it, Prog Ind HW30C, Prog Dymanics PD4645, Chill Grille, PML/Yourcovers.com deep alum trans pan, AutoMeter 8558 trans temp gauge, Roadmaster sway bar, Fantastic Ultra Breeze hood, added OEM parabolic mirrors and RH aspherical mirror.