05 F350 CC 4x4 long bed . After a hard acceleration(short freeway on ramp) turbo made a loud squealing as I backed out of the throttle. Now at take off from stop you can hear turbo spool up(much louder than normal) then noise dissappears, and when backing off throttle you can hear it spooling again. At shut down in driveway after key is turned off you can hear turbo still spinning down. Boost still showing good on dash gauge. Local shop gave a quick look see and said turbo was leaking (wants to replace). Any thoughts.