There isn't a drain plug on the transmission of a 2005 Chrysler PT Cruiser with an automatic transmission. These transmissions require a complete removal of the transmission pan to drain and refill the transmission fluid. If it has a manual transmission, there *is* a drain plug, but its location is specific to the manual transmission type and isn't easily described without knowing the exact transmission code.
In short: For an automatic transmission, you need to drop the pan. For a manual transmission, you'll need a repair manual specific to your vehicle's transmission to locate the drain plug accurately and safely.
