GM 6.0 gear searching.....

Nothing wrong with the truck. Mine likes 3k as well in direct in 4th gear. Remember 5th and 6th gears are both OD. You can lock out gears by selecting the M mode. I lock out 6th when pulling and will run in 5th. Now when I leave Florida and head through the hills, I lock out 5th and stay in 4th. Pulls really well for hours at 3k but no worries, I would rather pull at that rpm then to have the engine struggle in 5th, that's not good for the engine at all. Puts a lot of stress on the bottom end. 3:73 is a great all around gear and when in 4th your ratio is like a 4:10. I pull 10k of fifth wheel with my 09 6.0. Gas engines by design have to rev higher then diesel. No issues in doing this. Engine not screaming, not going to blow up. 3k is half the rpm range, diesels run half there rpm range all day. Your power band aka TQ and HP are gaining around 3 k and up, GM VVTi comes in to play around that Rpm giving max efficiency and power. Cold air intake, waste of money from experience, gearing to 4:10 will give better performance but expensive. Custom tune EFI live via Blackbear Performance for 600.00 is a great investment in my experience. I have one myself and stock verse efi live tuning there is a difference. No worries at 3k rpm btw, less strain on engine components, truck is by design going to run this way. GM 6.0 HD engines, last, they are a proven workhorse and will work beyond there service life of 200K, hence fleets all across the states use them. I have seen many with 300k running like new. Friend of mine owns several and pulls sheds around also construction equipment for his company. He works his 6.0 really hard, no problems, runs all day and always has a load on them. Last one he just let go had over 300k on it... reason he sold it cause his tranny gave out, truck engine wise ran great and had lots of power. His new truck, well it's another GM 6.0. So if you ask my opinion go with a tune.....especially Blackbear, you willl like it!