I-ring tubes are a problem. If you can, go to a later tune that uses the rubber sleeve going into the case. The tube is a smaller size on the newer tube and fits nice and tight , and if you are forcing the tube some to clear the valve cover or firewall then it is forgiving for that, where the o-ring tube isn't. I have had a few of the chrome tubes leak from the almost invisible seam. Hope that helps.
Also, transmission rebuilders parts supply like Dean in Agawam, MA have good quality tubes and sticks.