I've never pulled one from one of the old D4's myself, so school me please. I can understand how you get the oil pan down by doing what your saying, but I can't see the crank coming out the bottom like that. I say that because most of the CAT's I've worked on you usually had to have at least part of the front cover off for the nose of the crank to clear on that end. Then, on the rear you had to have the TQ or clutch, flywheel, and often the flywheel housing, etc, etc, off for clearnace on that end.
Like I said I've not had one of old 4's down myself, but to me what your saying doesn't make sense based on my past experiences. Please explain so I'll know better next time. Thanks, Wayne.