Thanks for the detailed testing procedure. When I did the first part of the test, I wasn't getting any vacuum on either port. I removed the assembly, which dumped out some oil, and when I had the unit in my hand and moved the U shaped fork inside back and forth, it did create vacuum out of the ports. I checked all the lines and they looked good. Getting to the transfer case switch is a major pain, so I am hoping that is not the issue. From reading the thread, it could be. I am confused now.