If this is sudden onset, I'd check the oil levels in the transmission, and the differential (if separate).
Might also be something to do with the speedometer, if it is mechanical cable drive, but it would have reached out and beat you to death if it was loud enough to notice at 50 mph.
My ex-wife always caused a whining noise when accelerating............
this could be a number of things'''''''from a bearing failure to worm differential gears.....
Hi the usual reason is a worn gearbox which is the most likely cause.
Your girlfriend doesn't trust your driving?
its usually the wife in my case
apparently started when traveling over 50mph in 5th gear but noticed again it is happening in 4th as well only when accelerator depressed. If you ease off accelerator noise stops. Car is a manual petrol engine, 46000 Nissan Note
