'87 300E 137K

So while i was filliing the transmission with sealant this afternoon, the 'radiator' symbol warning light came on on my dash. When i moved the car to see if the transmission was still leaking, there was antifreeze on the road!

I topped up the radiator header tank a couple of weeks ago and I'm thinking that was when i started seeing something dripping off the drip pan. The drips felt, smelt and looked like transmission or power steering fluid which is why i was topping off the transmission with sealant today.

OK - is there anything containing antifreeze that could be leaking and dripping down onto the flange between the bell housing and the engine on the passenger side? Or could it be the heater core inside the car? The engine is just so close to the firewall i can't see where the leak might be coming from...and if someone says 'head gasket' I'm not going to be happy.