I have a 2004 wv passant my gears won't change into any gears

Check to see if you have fluids in the trans. That pop sound could have been a line and won't shift cuz it's empty

Can you hear you engine rev, but the car doesn't shift gears? When it decides to shift, does it jump into gear. Sometimes does it sound like the car is humming because it's not ready to shift? IF so, your transmission fluid may have leaked out over time. I suggest letting the car sit cold for a hour or two. Pull out the transmission dip stick. Oil level should read between cold and hot. If low, google how much transmission oil is required for a dump and go to autozone or autoparts and ask them how much is required. You can do it yourself likely for $80, or you can get charged for $250 or little higher for the dealership to do it. This is the first thing I did when my mom gave me her jeep grand Cherokee 2000. It worked.

Oh, if you replace your transmission fluid, you'll need to get the fluid as well as the transmission filter, you'll also need to get a sealant and gasket that goes around the transmission pan so that you can seal the pan from leaking. Again, easy, but it will take you a while to do it if you never did it, or just pay the dealership to do it.