Noise from acceleration

[Londonbell]

Hey guys. 
My Aurion 2008 prodigy (122,000 km) was running well since last week we moved from Melbourne to Adelaide, I've been noticing the noise from the engine bay but not sure where is the faulty part.

The noise description is pretty much like this gentleman said: https://au.toyotaownersclub.com/forums/topic/35409-2010-aurion-zr6-vibration-sound/ 

You can hear the whirring noise when accelerating (not sure the condition between 1k-2k rpm), if the speed was held like 60kph (constant speed) the noise is gone. 
Since we arrived, I decided to send my car to Adelaide Toyota. They took my car and did a full inspection, and told me the problem is a bad alternator. OK, charge me $1,050 to fix it (700 part, 350 labor), when I pick up my car and I found the noise is still there... 

The problem didn't solve...

Today Adelaide 4S told me the problem is coming from the gearbox... to fix it may cost me $11,500, (yeah that's the number they gave me).
The funny thing is I just did my transmission service from Nunawading Toyota in Melbourne (charge me $380 without change filter) last month. And when I ask staff from there is anything wrong when I pick up my car last month. They said nothing to worry about...
I've been doing a lot of web search related to this problem but seems like the noise problem may link to the wheel bearing, cv joint, and idler pulley as well...

Any suggestions?

 

 

 

[campbeam]

A known issue is the idler pulley. It would be worth checking /do a diagnosis before throwing parts and labour.

Toyota Squeaking noise from engine compartment.doc

[Londonbell]

2 hours ago, campbeam said:

A known issue is the idler pulley. It would be worth checking /do a diagnosis before throwing parts and labour.

Toyota Squeaking noise from engine compartment.doc 218.5 kB · 36 downloads

Thanks mate.

We did let Toyota 4S do the checking before they throwing parts and labor😂 Question is they didn't find it... (and give me a new alternator...)
Now they offer me a free loan car and told me the wrong part is gearbox... I don't know changing the ATF and filter again will help to solve the question or not.
I'll pick up my car next Monday. Hope everything is really fine.