Transmission slips??

There are sensors on the top of a transmission where you can't see them from undernieth. Some of them include a seal that keeps the fluid in because what they sense has something to do with the fluid. There are also seals on the front of a transmission where it meets the engine and at the back where it connects to the rest of the drive line.

I've never personally seen it happen but it's not impossible a sensor vibrated loose and that's all it is. The sensor port that's leaking needs a few-cent (cost wise) washer (seal) replaced and put back in and it needs topped back off with fluid. That's the easist, and cheapest thing it might be.

It could be a coolant line that broke or came undone and isn't sealing properly anymore. Coolant line locations are different depending on the make and model of the vehicle and the type of transmission. Also not too bad of an expense to fix. These 2 are the ones you want to pray for that it is because the other possibilities are quite a bit more expensive because they're a bit more work and parts to repair.

If it's the rear yoke seal that's not going to be too extremely bad of an expense to have corrected either. If it's the front seal that's one of the things it could be that's going to be a bit of an expense you want to cross a finger or 2 that it isn't.

There aren't any kind of overflow safety valves or anything on an automatic transmission that it could be. Manuals have a pressure (different people call them different names, some call it a combustion cap, I can't think of all the names people call them) cap on the side of them that would allow fluid to leak out in the event that there's too much pressure inside. The cap blows off and releases the pressure to prevent damage. Engine blocks have these things in them too for the same reason. I doubt that's what it is though because if/when they blow they're gone and there's a nice sized hole fluid can get out with and there's pressure behind the fluid so it usually makes a noise when it happens you can't miss unless you're deaf and almost all of the fluid escapes.

It could be some other things, too, but the other things I can think of that cause slippage don't usually happen in combination (always) with a leak. A leak means someting broke or came loose. Lets hope whatever it is the leak is coming from didn't cause damage to anything else when it broke or because it's broken.

You're going to be told you need a rebuilt transmission. Once an automatic tranny slips it needs rebuilding or replacing.

find local shop at ATRA.COM for a road test. if its been leaking for awhile and its low on fluid you might of done internal damage. shop will let you know and at least give you an idea on a estimate to repair

Check the fluid level.  Service if required.  A transmission leak is not good news.  You might need a new transmission or it might be time for a new or newer car.  Good luck.

I wish I had better news, but no matter what you do or how much you spend, it will still be a  2007 Volkswagen jetta. 

maybe you should get a mechanic to check it out