Thanks for all the advice, Thought it may be brakes or brake dust ,but I've discounted that now , Think I may have not fully disengaged 4 wheel drive auto lock, had a bit of a play , and on the few times I managed to get a clear run to get up to 95 klm I couldn't hear the whine ( though I am a bit deaf!). will get it checked out for sure auto art sounds good thanks MT .Think it may be a case of me being new to the 4 x 4 world and the Patrol. Hope so , it wil be cheaper than a new diff!! I will let you know the outcome . Thanks again.