I just removed my transaxle and replaced my clutch. In the process that darn tube started leaking behind the water pump. My GM Manual refers to it as the Coolant Pump Inlet Pipe. No installation or removal instructions and not even a picture of it. I am going to try that "remove all the hoses twist and pull out" method and I will go to GM and ask for the O-ring. If they have it or will give me the size in O.D./I.D and cross-sectional diameter of the donut itself I will log back on and share the info. I will also let you know if this method works and if I have any further leaking issues.