Oil Filter Differences (6.0L)

[GASoline71]

I did a search and cam up zip, zilch... na-da.

2006 Chevy 2500HD with the 6.0L Engine. Looking at oil filters for when I change the oil. There is an AC-Delco PF-46E on the 6.0L right now. Was on there when I bought it at the dealer last month. So I was at my local parts counter (which is a mom and pop store with good knowledgeable people backed by Parts Plus), and asked them for an AC-Delco filter for my truck. She comes back with a PF-61E. Says that's all that the computer lists. I tells her that the truck has a PF-46E on it. Now the gals that work at this place know their stuff... so she was stumped as to why the PF-46E was not showing up for the truck, and only the PF-61E was.

Looks like the PF-61E will fit my truck. It is a smidge longer than the PF-46E. But after she and I did a little research it appears that the PF-61E has no "anti-drainback valve" in it where the PF-46E does. Soooo...

What the heck? What is this "anti-drainback valve" monkey motion, and does the 6.0L have this feature? My oil isn't due to be changed in a bit... so if I have to order a PF-46E I can. No biggee... but I like to support my local businesses when I can. Been going to this parts store for 20+ years.

Anybody got any info to share?

Gary