Turbo Advice KZN185W

[thethunderchild]

I'm new to this so please go gently with me. I work at a Citroen Specialist but a friend of mine has asked me to look at his 3.0TD KZN185W (don't know if the W is important). The Truck would appear to have developed a graunchy whine from the turbo that has gradually got louder over the last few weeks. Any suggestions? If it's a case of replacing the turbo where on earth can i get one semi-cheap.
Regards
ANDY
aka thethunderchild