Where is the transmission solenoid in a 1500 dodge ram 2003 5.9?

The transmission solenoid(s) in a 2003 Dodge Ram 1500 5.9L are inside the transmission itself, not externally accessible. There isn't a single solenoid; there are several shift solenoids and potentially a pressure control solenoid within the valve body of the automatic transmission. To access them, you'd need to remove the transmission pan and potentially the valve body. This is a significant job requiring specialized tools and knowledge.