I have an '08 CVT Patriot with a similar problem, maybe the same as yours: 8000 miles, repetitive rattle in gear particularly 1500-2000 rpm, can hear only with radio off - sound like a large but quiet cricket is underhood! Does not happen when car in neutral. Does happen when brake torquing in gear up to that speed range with vehicle not moving. The dealer could not hear it, so I took them on a drive and demonstrated the condition. It's easy to overlook this noise. To me it's not the noise itself that is bothersome but that it may be an indication of something out of adjustment and/or about to go wrong in a bigger way. They are going to look at it again tomorrow.