I noticed on the '82 300 SD that the rubber boot coming off the top of the VCV had worn through. I'm still working on my vacuum issues, so my tranny isn't shifting like it should. I replaced the rubber hose coming off the top of the VCV with a Y connector and plugged in the MityVac. It was reading 17 and increased with RPM. From what I have read, the VCV bleeds off vacuum from the bottom tube that goes into the cabin. If I disconnect the vent line and connect the MityVac to it then I get no vacuum when I pump it up, indicating that my vent line is not plugged. When I connect the MityVac to the vent connection, I get 0 vacuum regardless of RPM. I'm assuming that my VCV has failed. Is my logic flawed or are my assumptions correct?

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1982 Mercedes Benz 300SD w/ Greasecar Kit
2004 Ford F350 Dually
2004 Honda CBR1000RR
1992 Reynard Formula Continental