Turbocharger failing
 

Hi all,

I have a 1985 300SD with appx. 285,000 miles on it. While driving it today I noticed that it didn't sound as "clean" as the diesel normally did, and that it was making a noise like metal rubbing on metal. I opened the hood, and as best as I could tell the noise was coming from the turbo. The turbo charger was shaking rather violently and it was pretty hot as well. Is there anyway to mechanically inspect the turbo to find out for sure if I need to replace it? Thanks! (And if i do need to replace it, where's a good place to buy from?)