From what I have gathered from the forums and looking online, p/n 05011393AA Brake Booster Check Valve is NLA no longer available for my 96 Dodge Ram 2500 Cummins powered 2WD Truck. The typical help section / Dorman section of the local auto parts stores do not have checks valves as large as our trucks require. After countless hours of searching online to try to compare the hose size and grommet size of various check valves to no avail, it occurred to me to look at the one on my 91 Chevy 2500 2WD. Well it is very close in size. The ribs on the grommet side are a little larger, but it will push into the rubber grommet in the booster. And the hose size is close enough that lots of pushing will get it in the vacuum hose.

The part number for the Chevy AC Delco Valve is 18022219 / 179-1266. It is still available as of February 2019. $19 on Amazon.

As my search wore on, I realized that not only was my check valve leaking, my diaphragm within my power brake booster was also leaking. So I replaced the booster and got a new check valve with it. Advanced Auto Parts, Wearever part number 54-74803 booster comes with the check valve. It took three tries from Advance to get the actual Wearever brand. The first two were the same part number, but were different brands. One did not include the valve, the other one was lost as the box was mangled from shipping.

Hope this helps anyone in need of the check valve or booster.