I just put the 6.0 in the truck. Rear lifters from the sound of it are not getting oil. When the oil is cool, there is no tapping just the normal valve train noise, but when it gets to operating temp here comes the knocking. The oil pump, pickup tube that is in it came from my running 4.8. I wasn’t sure about the 6.0 pump and I knew the 4.8s made good pressure. I also noticed my oil pressure dropped for like 20 seconds and then came back while I was in the drive. So why is oil pressure doing this on the 6.0 and not on the 4.8? I suppose the fix would be to replace oil pump pickup tube o ring and lifters to cover both. Which sucks because I just bought headgaskets and head bolts.

I should of said in the post but I’m still trying wake up. The pickup tube and pan came from 4.8. I used the pan because it was already modified for oil return from turbo. The pan and pickup tube for the 4.8 and 6.0 are the same. 6 quarts of oil is the requirement.

I did use the 6.0 lifters. The rollers looked good and the stock cam lobes looked good. If it had lifter problems I would assume I would see wearing on cam lobes or rollers but they looked good. No wearing at all.

I’d guess it was the o-ring. Hopefully you didn’t hurt anything on your drive when you lost oil pressure. Cut your oil filter open on your next several oil changes to inspect for bearing debris. Keep an eye on oil pressure also.