I Found that WD-40 works wonders on the vacuum valve on the dash. I replaced all the lines with 3/8 brake line and vacuum hose on the ends. I couldn't get the valve to work. Finally I just let the vacuum pull the WD-40 in. The valve stopped leaking and it worked great. First I would take the pancake plate off the side of the diff and pull the shift rod back and forth to make sure it's free while spining the wheels
