ok, I guess I figured out what was wrong.
the "grid" settings was set to UTM at BaseCamp, when I changed It to be "Lat/Lon hddd mm'ss.s'' " it started working regardless of what datum was selected.
the "grid" settings was set to UTM at BaseCamp, when I changed It to be "Lat/Lon hddd mm'ss.s'' " it started working regardless of what datum was selected.