A few people have had this resolved. I currently have a case open and I'm waiting for a response from Chyrsler after two failed attempts to fix it.
My transmission was quiet when new. Around 1500 miles i started getting a slight rattle in 4th. Now i have a rattlesnake in all gears and a can with some marbles in it at idle. The fact that the noise has become worse, and that Chrysler approved two repairs already, tells me that they know it's not normal, but they don't have a single method to fix it.