I have a 2004 2500 5.9 turbo with 315448 miles on its the original turbo. What is the common mileage life expectancy of the turbo. The truck doesn't have the power it used to have also before i could hear the turbo spool up. now not really

 

I'd say it's shot by 300k miles. If you remove the cover and it wiggles you need new. Nothing lasts that long and works 100%.

 

How plugged up is your filter?

Take the inlet off and check for shaft play. It should have a tiny bit of in/out and pretty much zero up/down, although a smidge on dry journal bearings would be normal. It should NOT touch the housing though.