Transmission Identification

['02 H-D #677]

OK ... my brother wants me to help him change the tranny fluid in his '93 E350 van. I told him to get the appropriate gasket and filter. Come to find out, Ford installed one of three trannies in these things ... E4OD, C6, or 4R70W. The ID tag affixed to the side of the tranny is no longer readable/legible. I know it is not a 4R70W. The van has electronic OD so I assumed it would be an E4OD ... but ... I was of the understanding that the E4OD had a drain plug in the trans pan? This one does not. Did Ford equip 1 ton vehicles with OD configured with a C6? How does one identify one from the other?

[NDEBT]

20 pan bolts=E4OD

4X4 pans are the only ones with a drain plug in the pan.

['02 H-D #677]