you'll get an idea with some of my pics
this is inside the compressor(after removing the rubber pipe from turbo to maf/airbox)
hdseven is talking about a tip of the small blades braking off , the air turbulence causes a whine sometimes
this is the turbine (after removing the exhaust down pipe at the clamp)
this is getting a finger in to feel for free play from a worn bearing
don't be supprised if the blades are near to or touch the housing when bearing is dry with no oil pressure to centralise it, the clearances are very tight in there on modern turbos.
ideally you don't want to feel any slop by pushing or pulling along the axis of the shaft
How much shaft play should a journal bearing turbo have? - YouTube
heres my 40,000 mile turbo out of car
stilo jtd 40,000 mile turbo radial free play 0.3mm - YouTube
stilo jtd 40,000 miles turbo axial endfloat approx 0.1mm - YouTube
I have no vids but basically when I redid with new bearing kit etc it had nearly the same radial play was still just under 0.3mm (only 0.05mm better or less)and axial play went down to barely measurable 0.01mm- 0.02mm(I think was only 0.10mm old)
the bearing wear was not the reason I pulled this turbo, id say it was still good
hdseven can comment more on what play is too much
also id say plenty of turbodiesel owners have had a real bad police siren whine , some lasted not so long some lasted many many years and still going , its not necessarily a death toll( if it does turn out to be the turbo)
also theres been occations of people having replacement turbos fitted that have whined from new on the car.