Historically, Judaism preached of a soul that was inseparable from the physical body. The soul was the thoughts emotions, and life-force of the body, but it did not and could not exist separately. Although it was not a physical organ, it acted as a part of the body and could not continue on after death. This idea of the soul was based on what was directly stated in the Torah, the Jewish equivalent of the bible. Over time, as ancient Greek philosophy on the soul and Christian and Muslim ideas made their way into Jewish scholarly discussions, many Jewish thinkers began embracing the idea of dualism, the soul and physical body existing separately. In these conceptualizations, the soul exists more apart from the body and is more connected to the divine and spiritual planes. In addition, it can exist after the body dies and ceases to exist. Today, there are many sects of Judaism that embrace both ideas of the soul.
Only the original idea of the soul should be counted a Judaism. The dualism ideas of later years where influences from other philosophies, so they don't truly represent the Jewish idea of a soul. At its core, the soul is tied to the body and exists in the same subsequent plane.
[P1] The Torah characterizes the soul as reliant upon the body, and not continuing after death. [P2] As Jewish thinkers began to draw influences from other philosophies, the idea of a separate body and soul was embraced more widely.