Its on the back of the alternator, its back, and about 3/4" square. thats the part the tech tossed at me and said "this is whats been killing the alternators" I have in it in my glove box, kind of a "good luck charm" I suppose.

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Then it's definitely not a diode. Capacitor, most probably. A new alternator typically does not have the noise suppression capacitor installed, so the old one gets installed on the new alternator.

Can you provide an example of a specific automotive alternator with no noise suppressor capacitor installed?

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Certainly. The Bosch AL117X is normally furnished without a pulley, fan or noise suppressor.

To wit:
http://www.allpartsexpress.com/ShopByVehicle.epc?q=1982-MERCEDES--BENZ-300dt--/--L5_3.0l_diesel_turbo-Electrical&yearid=1982&makeid=MERCEDES+BENZ%40%40MERCEDES+BENZ%40%40X&engineid=1193767%40%40300DT++%2F+L5%5F3%2E0L%5FDIESEL%5FTurbo%40%40300DT&catid=Electrical&subcatid=Alternator,%20Rebuilt&mode=PA

The qualified observer will immediately observe that the is no suppressor installed on the rear of the alternator.