04 Ram1500 5.7 Hemi, reg cab, 2 WD, oil press issue.

Borrowed wifes truck, pulled in drive,
parked, and found engine compartment
literally drenched with oil. This happened
as i pulled in. In fact my daughter saw it
happen. Everything was soaked. Found
oil filter had split along the seam which
had some rust. Obviously the oil/filter
had not been changed as it should have
been. Not MY truck. That's another story .
Never the less it has become my
problem. The engine has had a slight tick
under right valve cover for some time. It
has 115,000 miles on it. I installed new
filter/oil (Castrol10w30 high mileage
synth blend), cleaned up most of the
engine compartment mess and fired it up.
Guages are all showing normal readings,
but have a check engine light, and
abs/brake lights that were not on before.
The engine runs smooth while still ticking
a little as it did before. The oil press is
immediately at the normal operating
press.(sorry no #s). Just as the engine
reaches normal operating temp, the
check guages light comes on, and the oil
press gauge abruptly drops to 0, and will
not come up with rpm at all. I have not let
it run much beyond this point. Have
started, and shut down engine several
times when the press drops (approx 7-8
minutes each time, in order to circulate
the new oil through the new filter (approx
1 1/2 hours total. Drained the new oil and
removed the new filter. Put samples in
mason jars, let sit over night. Looks good
no shavings or water, a little darker but
not bad. Repeated new oil (same Castrol)
and new filter. Same end result. Abrupt
oil press drop to 0 when engine
approaches normal operating
temperature, and will not increase with
rpms.  Any opinions would be greatly
appreciated ...