Loud Whining Noise When Accelerating, What Can It Be ?

It''s not extremely loud but its certainly loud enough to hear it when inside the car. A few weeks ago I heard the same noise but it was very quiet and barely noticeable, nobody else could hear it so I thought I'd get other repairs done and then sort that

last night whilst in 3rd gear going uphill, I was going about 45 mph, all of a sudden a loud whine like a balloon deflating was heard in the car. only noticeable on acceleration.

I watched some video's on YouTube of bad turbo noise and it sounds similar to the noise in my car

However my mechanic friend only replaced the bearing on my turbo a few weeks ago , he got the bearing from a car salvage yard. he had the turbo off whilst replacing my EGR valve and said the bearing on my turbo had play on it, so it made sense to replace it whilst turbo was off.

( He says he replaced turbo bearing but as I wasn't there I don't know this for certain)

I asked my friend if it could be turbo, he says it could be down to a bad gearbox ( we think it's failing due to clunking and shavings in gearbox oil) I think he is just trying to cover himself because he's not long said he's replaced the bearing on the turbo and maybe he doesn't want to admit he's not done a good job or that he has lied

He says if it was the turbo that the noise would be there all the time ? maybe it is but it's only more noticeable at high speeds as that is when I can hear it.

I'm also having problems with the wiring to the mass air flow sensor being damaged, could that cause the noise?

.

And does a turbo bearing sound similar to a bad gearbox noise whine?

thanks