talking of driveline noises....

at about 60 mph i hear a whine coming from the driveline, seems to be more towards the rear of the car, as i feather the gas pedal it goes away when i back of and comes back as i put gas back back on again. it goes away alltogether at about 70mph and cant be heard at 50mph either.

I have 42,000 miles and am i think the 3rd owner, i've been meaning to call isuzu and see if its covered under warranty but havent had chance yet.

Anyone have any ideas?

Pete