1969 Dodge Dart issue with installing axles after thrust block removal.

If the buttons are properly installed there is a through pin, looks like a finish nail, through the holes in their center. The pin is supposed to be staked on the pointy end so as to retain the buttons. Not all of them were which allowed the little buggers to come out on the end of the axles and fall into the banjo or tubes.
Years of struggling with dimensional problems caused by "green" bearings that resulted in stripped splines in the side gears or at the ends of axle shafts has reinforced my observation that Chrysler got it right in the first place with the adjustable tapered roller bearing with the end play spacer in the Diff. I got tired of buying axles, so all of my rear end assemblies have been switched back to OEM adjustable tapered roller bearings, which puts ME back in control of the critical axle end play dimension, and ensures total engagement of the two side gear splines on each axle.