My gearbox is making a loud siren like noise?

I have a 95 turbo diesel daihatsu rocky and the gearbox is getting a loud whirring siren like noise in it and it gets louder when I accelerate. What is causing this and what do I need to do about it. I have changed the oil and also added lucas oil into it.
Bec, January 2010


done
Take it to a garage before it siezes and the ensuing crash kills you or, worse, some other family.

idiot, January 2010
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