High Pitch 5th Gear Whine

[Circuit]

So I searched and could not find the exact answer I was looking for.

I have a high pitched whine in 5th gear only. It gets louder with speed, but can be heard @ any speed when giving it gas.

Any idea what this may be? Something wrong with the synchros? 5th gear? Tranny?

Thanks in advance!

[RABID_MP5]

Could be tranny bearings or 5th gear cogs are worn from miles or lube deficiency.