2007isx engine brake problem

[manny87]

Hi all.
I am having a problem with engine brakes of my truck, they work better when its engine is cold, but they do not work when engine warms up.
cummins guy changed rocker arms, shafts and couple of engine brake rocker arms, as they said, oil was leaking thru the wear on shafts and arms,
i changed sensors and wiring harness for sensors (under the rocker cover). Oil pressure on the dash shows little over 30 with at operating temp.
still engine brake doesnt hold or slow down speed of truck even with empty trailer.
pls suggest if some one have same problem or have any solution,