BMW Repair: Transmission 1989 325i, fly wheel, torque converter

Question
I get an occasional trip from the motor/transmission. I think its oil. After getting under the car i noticed a hole about 2"x3" were the transmission mount to the motor.I see a large gear(fly wheel?) and what i belive would be the torque converter housing. Hard to tell were the drip is coming from.   Should this opening be covered? there are no tapped/threaded holes to mount a cover. there is also an occasional clunk in the trasmission. Should I have this drip looked into immediatly or is this normal and all I need to do is cover the 2x3 hole?  

Answer
I'm not familiar with the hole you are talking about, but I dont think it should be open.

 Put a piece of white paper, or a paper towel under the car, and take note of the color of the drip.  If it's red... then it's ATF, if it's brown/black... it's engine oil.  If its engine oil your rear main seal is likely shot (common) if its red, then something in the tranny is leaking... and yes it should be looked at soon... You dont want to rebuild that tranny until you have to ($$$$)

 Hope this helps,
 Josh