Whining noise while accelerating

My 2018 Tacoma Crew Cab (4 cyl) whines whenever I accelerate, at all speeds. Kind of like the sound of a car horn behind me, only a little less loud.
It stops when I take my foot off the accelerator. It's definitely coming from the rear of the truck.

 

This is happening to my truck too. But I notice it when it gets cold and last for like several days then dies out. Just moved to Vegas and it’s getting cold but I just took a road trip to Utah and it started up again. It wAs 14 degrees there and worked it a little hard. So I’m sure it’s just whining because it’s too cold and I worked it too hard.

also when I first encountered this noise I brought it up to the dealer and I forgot what he said exactly but I believe it’s normal and comes from the fuel thingy/fuel sender? at the back right of the engine (looking at it from the grill side-if that makes sense) near the firewall. Hope that helps some what

 

I read in another thread (??) where several fellows recently had their fuel pump replaced (recall). No more whine.

US $0.02

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I had the same high pitch sound in 3rd gear, dealer kept my truck overnight and said it’s my AC Thermal Expansion Valve that I need to replace. I’m out of warranty so I’ll wait till the expansion valve goes out and I need to replace. Since you’re under warranty, I would have them change it out.

 

2021 SR5 Double Cab, purchased last week. Same noise. I will look into having Toyota replace the AC Expansion Valve.

 

that's exactly what mine sounds like

 

My2019 DCSB TRDOR, had the rear whine since I bought it, at 30k miles it got worse.

I drained and measured the diff fluid, it had less than 3.2qt in there, should be 4qt. by the book.

Refilled with

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 Castrol full synthetic, it got much better instantly.