Hey all,  new to the site so not sure where to put all that is done to the truck.  Real fast, the motor was rebuilt 36k ago new everything internal and head (minus crank & rods)  new vp same time, s300 a little after motor new fass150 new 100hp injectors from same shop that built motor, everything done by same shop , 6 money ago started getting blue smoke and "alot" from exhaust pulled turbo had rebuilt, guy said labyrinth seal was coated so rebuilt!  3 days later smoke again.  Took back to shop wyd time saI'd cartridge was worn? Replaced!  A week later still smoking.. weird thing it only puffs small amount when starting then has to get warm to do it again and only when on compression letting motor slow truck down (6speed)..  it don't smoke when accelerating or idle just when slowing down letting off pedal?? Please I need help 

I can't really give you a good idea of what you could be experiencing, especially since the motor was just rebuilt. I'm sure @TFaoro will be able to point you in the right direction as he's he rebuild master around these parts!

Blue smoke is typically oil getting into the cylinder. Now is the blue smoke only at startup? Or... Is it even after being warmed up? Blue smoke on start up that points to valve seal typically. I would inspect air tubing for oil coming from the turbo.