blowing transmission fluid 1980 full size Bronco

I recently replaced an engine in a 1980 full size Bronco. To make a long story short I ended up with water in my transmission fluid the day I noticed this I drove home (approx. 25 min. drive) and parked about ten minutes after stopping I noticed transmission fluid leaking, crawled under to find leak was losing fluid next to dipstick above pan (vent?) had transmission power flushed that same day and removed most water about a week later after about 30 -40 min. drive had same issue, any ideas as to what I may be dealing with.
Thanks,
Rick Have you checked to see if you are still getting water in the transmission? Do you have an oil cooler? Could it be possible you have a cross-leak between the transmission oil and the coolant? Maybe coolant pressure is causing your blowout problems. Check this out before it gets worse. I appologize, I failed to make clear that the water was from the engine r/r. I had to replace a new motor (550 miles) due to oil pressure failure. While fighting with the re-builder over their waranty (haireline fracture in block) my engine was out for about 5 weeks in Seattle with no garage, I failed to think about position of truck and possibility of water running into removed dipstick hole. Water is not coming from cross contamination (radiator oil cooler). My problems are 1. how do I eliminate small amount of water still in tranny and 2. why am I blowing fluid after resonable length drive (not every time)?
once again thank for your time and help,
Rick I did a simple experiment with a test tube. The result showed that transmission fluid and water don't mix -- and that the water sinks to the bottom. So there's your answer; drop the pan and replace the fluid.

Incidentally, this result explains why a transmission flush does you no good. They simply scoop off the upper layers of the fluid. The flush probably did not remove a single molecule of water.