I have a 1994 Hilux (4Runner) 350,000miles on the clock, 3lt Turbo Diesel and still runs like a dream.

The problem I have is that in third gear, 3000rpm, the Turbo starts to scream and its extremely loud. It does not happen in any other gear even upto 5000rpm in the other gears. Should I be worrying about this or is it just normal?

Stephen