* Different trims: The 2004 Passat came in several different trim levels (GLS, GLX, W8), each potentially offering different transmission options.
* Engine choice: The engine choice also impacts the transmission. Was it a gasoline or diesel engine?
* Automatic or manual: Do you want to know if it has a manual or automatic transmission?
To give you a more precise answer, please tell me the following:
* What trim level is your Passat?
* What engine does your Passat have?
* Do you want to know about an automatic or manual transmission?
Once I have this information, I can tell you what type of transmission your 2004 Volkswagen Passat likely has.