Technical 3.0 manual gearbox problem

[pogo001]

Hi.
I recently noticed a high pitched whining noise from the gearbox area on deceleration in gear. It's the 2013 3.0 6 speed manual box. I don't think it's clutch related as it isn't connected to depressing the clutch pedal. However, if I touch the throttle , it goes away and drives quietly. It's never happened before. Its also a little irregular, sometimes barely audible.
Does anyone have any knowledge of possible issues?
Thanks in advance

 

[bugsymike]

Others may be able to give better advice, but I have found differential gears, as in crown wheel and pinions gears when worn or not correctly in mesh can give a noise which changes when on the "over run" or deacceleration when compared with under load due to movement in the differential gears.
Unfortunately if this is the case probably not a cheap repair.
I assume oil level and type is correct in gearbox.

 

[jackwhoo]

replace or check transmission oil.

 

[AnthonyH]

A high pitched whine is usually the alternator. Also a lot cheaper than a new gearbox.

 

[bugsymike]

A high pitched whine is usually the alternator. Also a lot cheaper than a new gearbox.

In general I agree , however OP said"I recently noticed a high pitched whining noise from the gearbox area on deceleration in gear."