After finally getting my truck to run right again, I have a rather odd problem. The Check Engine light stays lit, and reading the code gives a 4.2, which the manual says is no Vehicle Speed Sensor signal. Google says that for a manual transmission, the VSS is somewhere inside the speedometer housing. But what's strange is that the speedometer hasn't worked in a decade or so, because something inside the transfer case strips the plastic drive gear. Yet I never had the CEL illuminate in all those years, Anyone have an idea what could be causing this, and how I can get the light to go out again unless there's a real problem?