Same thing, just the years, older I think early 80s and back have 2pc and the later yrs have 1pc, the rear main seal pretty much means its on the bearing itself, and the rear seal is on the back of the block.
"Its a Ford. Nuff said. Everything else is just a glorified tonka toy"
"ASE" Certified" Parts Professional
92 F150 302 4x4 Long bed Extended cab
2001 Taurus wagon