ben47, You totally missed the point of my reference to my GMs lubricant remark. It's an "ADDITIVE" to help prevent a problem in their differential.(and it works) Just like Dodge supposedly makes an "ADDITIVE" to help alleviate a problem with their Viper transmission. I only mentioned it because +^+^'s transmission was making the same noises as the transmission in my Viper was making. (or at least it sounded like it was the same from his description).
Sometimes after an "owners manual" get printed, problems show up, and industrious engineer's come up with a simple solution to the problem.
I'm not saying there is a simple fix for the "transmission rattle" that +^+^ spoke of, but maybe there is. And if there is a factory part #'d "snake oil" out there being offered for one Chrysler division, maybe there is something like that for the Crossfire. Possibly all it would take is finding a savvy "parts" guy or girl to find it. If it does indeed exist.