I will add oil to my truck so that its at the top of the full mark and after a couple days it will be to the add mark but will never go lower then that l. Any ideas?

 

I'm guessing you have a leak.... put some cardboard under your truck at night and look for drips would be the first step....

 

truck doesnt leak any oil. is there any way to tell what part of the engine is burning oil? turbo,valves,rings?

 

come on now...every 2nd gen dodge with a diesel in it leaks from somewhere. scratch that, every diesel leaks from somewhere. your 100% positive that its not leaking from ANYWHERE? take a look at the blowby tube with the engine running. Lot of haze/oil spitting? put your finger over it, feel like theres a lot of pressure there. take the oil filler cap off, lots of blowby pouring out?