Where is the transmition fluid dipstick located in a 1998 passat 1.8 engine?

I have a 1999 Passat 1.8L T and I'm sorry to inform you we have no dipstick. They have sealed transmissions and require to fill them by the top with a 17mm hex to remove plug. Good luck cause I'm having a bit of an issue right now trying to change the seals for the axles and have to replace the fluid also while I'm at it.