The exhaust side impeller on my turbo is chewed up.
1. Is it possible to just replace the impeller?
2. What would be the best place, Cummins, dealer, other?
3. About how much should it cost?
4. Is there an upgrade since I have to replace it anyway?

 

1. No
2. Dealer will cost way too much
3. Depends how bad it is, maybe new turbo"$1000+"
4. If you replace the turbo id get an aftermarket one for the price and performance, especially if you plan on doing a lot of upgrades.

 

You'ld need someone that works on them to tell if the housing is good / repairable [ there is a very close tolerance between the impeller & housing - if the impeller has a problem then its going to hit the housing ] .
But like Ryan said , this is a good point to upgrade , the tricky part is , which one to get , with yours being bad , you do not have the time to read [ for choice ] or shop for deal .
There are 2-3 names that are mentioned here frequently , site adds also .