There is a circular hole on the top back of my transmission, and i have no idea if its supposed to be there or not? Whatever is in there spins fast when the engine is running. Take a look, any ideas? Im quite concerned. Very new to volvos. The transmission is the 4 speed auto in my 1996 850 GLE 10 valve. I discovered this while trying to diagnose a very bad oil leak.

Here it is spinning

When engine is off.

 

That's the torque converter in there, and it runs in air (not supposed to be sealed up). I do there it is supposed to be plugged up just to keep nuts and bolts out.