Ok Jerry, so what you're saying is it's normal for the shaft going to the diagram to spring right back in when pulling on it, right? So when vacuum is applied to the outside of the diaphragm it will pull the shaft out some and engage the high range. That makes sense to me now.
When I jacked up one wheel and spun it by hand I was of course turning the driveshaft too, then tried to switch the vacuum back and forth expecting to see a change either faster or slower to the driveshaft rotation but I saw no change, that's why I thought the shaft or something must be stuck in low. It must need continuous vacuum then to hold it into high range, correct?
