Hi Makomark! Thank you for your advice! There was no water, no overheat and cap was still on with spring action. The port has provided an abundance of mystery since it is suspected of being clogged and the culprit of a blown front seal two years after the tranny was rebuilt! So the tranny has been taken out two times! We put it back in after it was cleaned, but I did not know the mechanics of its function. Is there a check valve in there that could have been stuck or damaged?? It turned out that the fluid ran out from under the cap like a tiny volcano during idle, but it stopped when it was put in gear. I change the port this weekend and ran the boat for 4 hours at 28/2900R and she did not leak so I think the problem is solved. Since that tranny was removed two times, maybe the port was damaged from impact from all the moving around of such an awkward and heavy beast.