Diesel Bombers - Hello, another newbie here

My name is Jeremy, I live in the Sacamento area of California. I have had three cummins pick ups, never should have gotten rid of my first one. 1st was an 01 dodge 3500 dually 6speed h.o.; sold it with 500k still running strong- the only problem it gave me was a throw out bearing.
2nd was a 98 2500 and tons of upgrades, only sold it due to not passing California emissions with 250k on it.
Currently the only one to give any problems an 01 3500 dually with an automatic, currently lost the vp-44; which is why I am on here. Hope to soak up as much info from you guys who have been-there done that, so I know what not to do, and what is tried and true.