Remove the hose at the turbo inlet and check the wobble in the axle of the turbo wheel. Should be way less than 1mm. More and you need to rebuild the turbo. Remove the turbo to intercooler hose, and check the inside for VERY oily deposits, a sign that the turbo oil seals are leaking. Remove the turbo oil line at the turbo and make sure it's puking oil when you crank the truck. Don't let it puke for more than a couple of seconds. Remove the turbo oil return hose at the timing cover and check for oil returning to the pan.

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