help engine or trans prob

[7.3ford350]

well truck was doing great today, didnt have a licks bit of problems. all of sudden we started hereing a knok every now and then but it wouldnt be consitent and would only be do it at low rpms and at idel. just had trans gone thou last then 1000 miles ago. even took the chip out to let the trans brake in without all the power going to it. i cant tell if its coming from the trans or the moter and also when its sitting there ideling for 5 mins or so it will start to blow blue smoke like its burning oil. i am clue less. i dont no where to start looking or what to do. please help .......
this is on a 2000 f-350 7.3 with 71,000miles

[SCUFFY828]

possible to have a fuel knock , due to a lean condition, may want to run a fuel pressure test, make sure oil is full, alot of times if fuel pressure is low will smoke