I have a 98 Expedition 5.4 EB with what I believe is an acuator issue. I have lights, a new t/c motor, can hear the clunk in 4 lo but no engagement. I live in Michigan and only use my 4x4 in the winter. It worked last season, but this year, nothing. I will go through the diagnostics you clearly outlined. I have a question: When you say "spray the vacuum cylinder" and manually work it, what should I spray it with and where should I spray it? Also, how do I manually work it? Is there a visable post I will know to grab? Thanks in advance for the help.