I have a question i have a fresh build 5.3. We fired it up for the first time last weekend. I fired it up the lifters cladded for a second then stopped. So i began to top it off with transmission fluid and coolant as it was running for about 15 mins. I went to shut the truck off and noticed the oil light was on so shut it off. Did some research and found the barbell plug was most likely to cause. I pulled the trans today and the barbell was missing. Does anyone know if i hurt the motor with it not being in there? Thanks

 

If only the barbell was missing then the oil was not filtered. If rear facing block plug was missing then you pumped oil out of the engine and not where it was supposed to go. Can you clarify what happened?

 

The barbell does 2 things:
- directs oil flow to filter,
- plugs the galley at rear of block.

Without the barbell, oil will leak from the galley.

 

sounds like you got oil pressure if your lifters quit clattering.
hope for the best and expect the worse, or pull it apart to ease your mind.