Faint whistle or whine while accelerating

My 19 does this too. I believe it to be the planetary gears in the transmission on the underdrive gears. It seems like it goes away in 4th and the two overdrive gears but I need to verify that with my scangauge next time I’m out.
Either way, I’m not worried about it.
I look at it like rear diff whine for the tranny

 

The noise here is AC related. Shutting AC off instantly stops it, even mid noise while it’s doing it. There are probably other similar whines but this once comes from right in the middle of the cowl/engine bay, and is AC clutch.

 

I'm assuming it's just an annoyance and if I don't do the fix it's no big deal? Or is it something that if I don't fix the AC clutch going to explode eventually, like when I'm out of warranty?

 

It's an AC expansion valve. Perfectly normal apparently.

 

About 4 years ago when we remodeled our kitchen we bought a new Frigidaire Gallery refrigerator. The thing made so many weird noises that were perfectly normal when it goes through it's various maintenance cycles that Frigidaire actually put an appendix in the back of the owner's guide that had a table listing all the noises and what was happening. This apparently cut their warranty service calls significantly. Might be an idea for the Tacoma owners' manual

 

My 22 year-old Admiral has done it since day one. Still running like a champ.

 

And hopefully so will my truck

 

I've had the same thing on my '19 and have just dealt with it. I'll try the AC on/off like people have suggested.

The noise got lower when I lifted and changed tires, but it's still there.

 

This is EXACTLY what mine sounds like.

My 2016 v6 didn't do it. My 2021 i4 does. I don't think its anything to be concerned about, but it is a little strange.

 

Here we go. Finally got Toyota to admit it and fix it

 

Sweet! How would I go about getting this fixed?

 

It’s a TSB, so you just go to the dealership and tell them to fix it

 

Please follow up and let us know how it goes. What they have to rip apart or any issues after the repair.

 

Nice find. My 2017 has been doing it since new but not as frequent or loud as before. It still blows ice cold air even in the 100+F SoCal heat in summer traffic .

 

Will do. But it’s just a full dash rip apart to get to the fan assembly. Then it gets replaced! Curious what the part difference is.

 

Just took mine to the dealer. They heard the noise and are ordering the parts. Should be done next week. How involved is this repair? Anyone know?

 

like I just said in the prior post, it’s a full dash removal. Also bolts from the front cowl. Not a quick job

 

thanks! Glad I don’t have do do it.

 

I wonder which is worse. An occasional whistle or a creaking dash after the repair

 

I was just thinking that myself. My truck does it from time to time, more so when I'm heavy on the gas. But, my truck has zero rattles in the dash. Wonder if I'd be trading a whistle for a rattle.