why is it that when i dont drive the truck for 2+ days it is a lot more quiet until i drive it and it gets warmed up. Is it the valve backlash or do i need some high mileage synthetic oil, maybe a little thicker. i use rotella 10w40 usually.

 

You don't need thicker oil. 40 wt at operating temp is just right!

RJ

 

No...your ears are punishing you for denying them from hearing that engine run for a few days.