with pleasure, and i appologize in advance for being long winded:
starting in 1995, the vulcan recieved a distributorless ignition system (DIS). this system uses a set of positioning sensors, one on the engines crankshaft and one on the engines camshaft, to determine when to fire the spark plugs. since the oil pump is driven by the camshaft via the distributor on this (and many "V" pushrod engines), ford could not completely do away with the distributor. the bottom half that engages the camshaft and drives the oil pump would have to remain (less ford redesign the entire block). since the bottom half of the distributor would have to remain anyway, the easiest way to retrieve a camshaft position signal would be to mount a sensor right on top of this "cam syncro shaft".
the cam syncro shaft has a small metal flag on the top of it. the camshaft position sensor bolts to the top of the cam syncro shaft, and this metal flag passes through the sensor...in this way the engine knows exactly where the cam is in its rotation (and thus, when the #1 cylinder is on its compression stroke).
heres where we get into trouble.
the cam syncro shaft rides on a set of bushings. for some reason (and this doesnt appear to be a problem on distributored engines for some reason), these bushings seem to wear prematurely, thus allowing the cam syncro shaft to wobble. at this point, the cam syncro shaft will usually emit a noise very similar to a belt squeel (but not always). if left unchecked, the bushings will continue to wear to the point where the metal flag that is supposed to pass through the cam position sensor contacts the sensor. this puts a sudden hault on the cam syncro shaft. the gear that engages the camshaft itself is nylon, and attached the the cam syncro shaft with a roll pin. the force of the cam syncro being stopped and the cam still spinning either rips the teeth off the nylon gear or sheers the roll pin...either case causes the cam syncro shaft to disengage the cam. with the syncro shaft no longer turning, the oil pump is no longer turning, thus oil pressure drops to zero.
it can take a matter of seconds to completely destroy an engine while driving at highway speeds with highway loads and no oil pressure. even if you see the oil light come on, you might not be able to safely pull over and shut the truck down in time to save the engine.
my truck, being a '93, doesnt have this problem. but if i had a DIS 3.0, heres what i would do: if buying a DIS 3.0 with more than 80K miles on it, replace the syncro shaft. after that, pull the syncro and check it at 50K miles and replace again every 100K miles. dont ignore squeeks or long engine cranking times, as these can be indicative of cam sensor or cam syncro problems. if your oil light comes on while driving, as soon as its safe to do so, put the truck in nuetral, turn the ignition off, and coast to a stop. these trucks (that being rangers in general, not just the 3.0) are known for having flakey oil pressure sending units that like to give false low readings. your next step in this situation would be to varify either low oil pressure or a bad sending unit and take appropriate action.
tomorrow, i will try to remember to look around the shop and see if i can find an old cam syncro shaft lying around to take a picture of.
again, sorry for being long winded. i hope i covered everything.
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