... Ok, I'm not the expert here and just trying to help you work this out.... on some of the bigger trucks were they not 2 pieces?
Also, when you slid the collar back you may not "see" the bolts holding the driveline to the back of the tranny but maybe its because the "locks" oare bent over the nuts and you can't see them??? Once you get the bolts loose their are usually little "cups" that pull back out of the tranny tail shaft...that is on the pickups.
And, as Hotrod Lincoln said, I have also read sometime/somewhere that it may be necessary to unbolt the rear housing and pull it back?
Hope all this helps lead you in the right direction.