[corn]

First thing to check & Im pretty sure you probably have already is to make sure its not overfull or foaming. Have you for sure narrowed it to the tube connection? Maybe one of the cooler lines leaking? I had a TH350 years ago that gave me dipstick problems. I took the tube back out cleaned everything real good & smeared silicone around the grommet & tube & reinstalled it. Let it dry good before you drive it though & it worked great. No real clue whats wrong with yours, just tossing out ideas. Hope ya get it figured out...