First post...MB virgin, be gentle with me.

Background: '87 300E, 137k, sat motionless in a driveway for 4 months before i bought it at the beginning of september. no leaks on driveway when purchased and no leaks until last week.

Problem: Fluid collecting in drip pan under engine and then dripping off back of pan. 1 drop every 2-3 seconds when engine is hot and ignition is turned is off. Stops dripping eventually - haven't hung around long enough to see how long. Fluid feels, smells and looks like either transmission fluid or steering fluid. Level of fluid in steering pump reservoir appears to be holding at about 2" below top. Drip pan appears to be too far forward for it to be a transmission leak however transmission is clunky and i'm not sure if it's changing up at correct engine speed - seems to be too high. Have not checked transmission fluid level when engine is hot and don't understand markings on dip stick yet anyway!

Question: where do i start looking?