How do you check transmission fluid level for2004 volkswagen beetle?

VW will tell you that the Transmission Fluid & fuel filter should never be changed. My Service writer @ the dealership says they should bechecked/ changed wth every tuneup. When I took my Beetle to a local garage,the mechanic changed my fuel filter and showed me how it was full of water (my car was running rough). Anyway,call a VW dealership service dept. and ask them to show you how to do this.