1995 Ford Aerostar

Engine Cooling problem
1995 Ford Aerostar V8 Two Wheel Drive Automatic

My areostar just stared to have a leak, but we are unable to determine where it is leaking from. The fluid is from where the trans and the engine attaches. It is not a hose that we can see, we did a pressure test and could not make it leak. We put it up on a rack an ran it for 20 minutes and no leak but as soon as the tires touched the floor it started to leak. Any IDEAS.
Charles kline
October 11, 2010.

Can you tell what type of fluid it is?