That's the part. The diaphragm is the yellow part closest to the plunger. Once you get it out, you can pull the plunger apart to remove the diaphragm and check for tears.

 

Got it off (had to take a small hose from radiator into the turbo off-lost some fluid)...but, this thing looks good to me? which sucks, meaning the 'easy' fix is not going to be for me?

 

Nope, sorry, that one looks pretty good.

Triple check all the vacuum lines from the pump to the control solenoid, check the pressure tank under the intake manifold, and the vacuum lines to the wastegate. It will take some time and effort to trace them all and check for cracks or leaks, but it could save you from buying a new turbo.

 

Back on the "do I need to replace turbo" kick, forgot I went down this rabbit hole before.
Check my video in here, the wastegate is HELLA rattly right?
https://www.dropbox.com/scl/fo/nu624...nkeqcsb1e&dl=0

I am going to try that vaccum suck trick with my brake bleeder tool-but gonna need a borescope to see at the wastegate...been wanting one of those cams, Amazon has some cheap crap that might get me by...if I did the Vac test on a mounted turbo, and lets say I had a camera in there to see, is there something i'd be looking for? I'd imagine taking the vaccum up to 15psi it should hold? but if the wastegate was bad, it would loose pressure?

Edit 2-got a borescope-not a chance the camera head is fitting into o2 sensor haha. Oh well.