I'd like to know whether der Teil actually means something different than das Teil.
According to this article in Der Spiegel, the meanings are as follows:
Der Teil (Teil eines Ganzen):
der Erdteil, der Landesteil, der Stadtteil, der Elternteil, der Bestandteil, der (vordere/hintere) Zugteil, der Mittelteil (z.B. mittlerer Abschnitt eines Buches)
Das Teil (loses Stück):
das Puzzleteil, das Ersatzteil, das Einzelteil, das Altenteil, das Oberteil, das Plastikteil, das Wrackteil
A puzzle piece is a part of a whole puzzle, for example.
Did they just make that up? Who said so? How thoroughly did they differentiate between regional variations and semantics? How is this different than when my two South Tyrolean friends explain that the one says "der Knödel" and the other says "das Knödel"? Is there anybody out there using forms in contexts that do not conform to "norms"?