Hi all, Over the past few weeks my 2004 530d has started to make a loud whining/chirp noise when the boost starts to come in. It doesn't do it all the time and only seems to happen in higher gears and lower revs under load .also When it happens the boost cuts in and out and the car starts to buck/kangaroo. I have checked the play in the shaft of the turbo and it seems a bit excessive to me as in the compressor wheel appears to touch the housing but I can't see any scrape marks. There is no excessive smoke coming out of the exhaust. I'm leaning towards changing the turbo but just wondering if there was something else I should be checking. Any suggestions would be great. Thanks in advance.