While catching up on some reading the other night I ran across this info for 03 6 speed owners so thought I would share, its probably old news to most TDR'es:
Rattling noise from transmission. Dodge wants you to know that some 2003 Ram Trucks equipped with the 5. 9L Cummins turbo diesel and six speed manual gearbox (build date on or before 5/11/03) are prone to giving off an annoying rattling sound from the transmission while idling with the gearshift lever in Neutral. Insufficient tension in the clutch disc springs is the likely cause of the noise complaint.
To check things out, set the parking brake, place the transmission in Neutral and start the engine. If you hear the noise, depress the clutch pedal and see if the rattling sound goes away. If it does, that tells you that the clutch springs just aren't up to the job at hand. Replacing the clutch disc with a new design unit (Part No. 52107775AC) with upgraded, beefier springs should help restore some peace and quiet.