^ me three! High octane AND octane booster? Just give $50 a month to a local charity, run lower octane, and all is good!

 

That's where I was going with that -- either there's a really serious loss of oil control (blown plenum gasket, wicked sloppy valve guides, etc.) or that SCT is tuned beyond insanity.

 

There is a tsb on the transfer case saying that it can rattle at a certain speed and rpm. It usually occurs around that speed and at about 2000 rpms. Mine does it. The fix is to bend a lever out a bit. It explains it all in the tsb if you search for it. I haven't done it yet to see if that fix works or not.

 

That was what i was wondering.. I kept searching for anything on tc noises but didnt come up with anything yet i will look into that. That is what i have been thinking the noise was. From what you have said it matches my description so far.. Thanks

I run the octane because i have a case of it that has just been sitting around and i figured i would use it until it runs out.. The truck seems to like it too. I havent been able to get the intake off yet to look in the tb for oil due to it being a pita but i have hardly a 1/2 qt of loss in oil every oil change and i get 14 mpg with 35s and 4.56s so i figured i would fight that battle another day.. Detionation sounds like valvetrain lifter rattle and that is not this sound, I can get that rattle if i run the performance tune and regular gas going up hills though so i know what you guys are saying but im certain that is not it... I should mention that this also has happened to me just merging on the freeway with no grade to it at all around 50 mph then lightly speeding up to about 60.