New 2021 CM Squealing Noise

I am making this thread for another reference in case someone else runs into this issue.

I just got my 2021 MGM Platinum on 8/30 with 2 miles on it. Yesterday while out driving a very loud squealing noise showed up out of nowhere. I stopped the truck and the noise slowed down with the vehicle speed and stopped when the truck stopped. I got back on the road and the noise didn't immediately come back, but came back once I hit ~35mph.

I rolled down the rear window to listen and recorded this:
https://youtube.com/shorts/1TWiilbixPg?feature=share

The truck only has 250 miles on it. I searched the forum and there was one other member who had a similar issue. He listened to the noise and said it's the exact same noise. The dealer has narrowed his down to the dust cover on the rear differential. Since mine just happened yesterday evening, I have not contacted the dealership yet.

I'm pretty bummed to drop some serious coin on what is known to be a rock solid platform, only to be taking it in with 250 miles on it. I also understand the manufacturing process will never be perfect. I'm sure the problem will be resolved. Will keep the thread updated.

 

That almost sounds like wind noise on a partially cracked window which would make sense if it starts at 35mph nothing else rotating would start a certain mph that I can think of.

 

Yeah the windows were the first thing I checked. It sounds much worse in person. Terrible noise.

 

Here is another video from today.
https://youtu.be/yuK3-GWyBPE

 

https://youtube.com/shorts/E_wcAWWwsss?feature=share

 

That is the same noise from my 2021 trd pro.I took it to the dealership and its the rear diff dust deflector.

 

Yes that is the EXACT same noise. It almost has an 'electric motor' sound to it at first. She's going to the dealership Tuesday to get checked.

 

Managed to grab a few shots by the rear diff with my GoPro today. Can't say it helped narrow anything down but I'm convinced it's the same problem @Glennjc1978 is dealing with. It's going to the dealership tomorrow for diagnosis.

https://youtu.be/tif0-m4CN7k

https://youtu.be/BbWbFs-cPKc

 

Well it looks like the same problem!

 

And for some reason i always hear a click a second before it starts making the noise.

 

Yes me too. Very faint, but it's there.

 

I got the truck back yesterday. Here is a synopsis of what the dealership said:
They worked their way down the driveline with lithium grease to locate the squeal. Sure enough it was the rear diff dust shield, same as @Glennjc1978. They somehow were able to look at it and see it was not damaged or out of round, but dry. They lubed it up and the noise is gone...for now. The lead service tech at the dealership told me the Toyota field tech has only seen this on a 4 Runner before. It was over a year ago and his Squeal never came back after applying the Toyota lithium grease. If it starts up again they said to bring it back and the dust shield will have to be replaced.

As the owner of the truck I'm not sure this is the real solution as much as it is a band aid, but I'm still hopeful it will be fine. I'm not super eager to have the rear dif opened up but I also want the problem ACTUALLY fixed. Hopefully the grease was enough, but I have my doubts. For now the truck is squeal free and I am enjoying having it back. The Tacoma loaner they gave me was TINY inside.

 

Where exactly is the rear diff dust shield? Are they referring to the brake dust shield?