i drove my 2005 chrysler 300 to town, on my way back my RPM needle went to 4 when i was doing 40. does that mean my transmission is slipping?

Hello, It could be a host of things causing this, and slippage is only one possibility. For example, there may be a condition which caused the transmission or powertrain control module to kick it out of gear. Have it diagnosed professionally to get to the bottom of the issue, and avoid driving the vehicle to prevent further damage.