[redmodelt]

The snap ring holds the speedometer drive in place on the driveshaft and can only be removed with the rear end out of the car. The roller bearing is behind the speedometer drive, again same thing. Except for removing the speedometer cable to get it out of the way, the housing it mounts to has nothing to do with removing the rear end, but best to remove the housing so it does not get broke. Sounds like the splines are jammed or rusted together from lack of lube. If you can turn the driveshaft and shake it some, might work loose, but be prepared for it to drop if it comes loose and rolls back.

It sounds like you might need to get a repair manual that shows the layout of parts if you do not have one. While I do not have one at hand, I think the Snyder's catalog has a diagram and parts number in it for the rear end.